基本情報

所属

• 北海道大学病院　中央診療施設等

職名

• 助教

学位

• 博士（理学）（北海道大学）

ホームページURL

https://gbmse.med.hokudai.ac.jp/%7Eryusuke/

J-Global ID

• 201301093647285278

研究キーワード

• 強度変調放射線治療   放射線治療物理学   データベース   放射線治療   モンテカルロ法   体幹部定位放射線照射   炎症性発癌   非線形最適化   量子線シミュレーション   

研究分野

• ライフサイエンス / 放射線科学 / 医学物理学

担当教育組織

•  修士課程　医理工学院
•  博士課程　医理工学院

職歴

• 2022年01月 - 現在 社会医療法人 恵佑会札幌病院 非常勤 医学物理士
• 2013年04月 - 現在 北海道大学 大学病院 助教
• 2008年04月 - 2013年03月 北海道大学 大学病院 特任助教
• 2007年12月 - 2008年03月 北海道大学 医学研究科 博士研究員
• 2006年07月 - 2007年11月 北海道大学 理学研究院 博士研究員
• 2005年04月 - 2006年06月 北海道大学 ベンチャー・ビジネス・ラボラトリ 非常勤研究員

所属学協会

• 日本物理学会   日本放射線腫瘍学会   日本医学物理学会   

研究活動情報

論文

• A new predictive parameter for dose‐volume metrics in intensity‐modulated radiation therapy planning for prostate cancer: Initial phantom study

  Yuki Saito, Ryusuke Suzuki, Naoki Miyamoto, Kenneth Lee Sutherland, Takahiro Kanehira, Masaya Tamura, Takashi Mori, Kentaro Nishioka, Takayuki Hashimoto, Hidefumi Aoyama

  Journal of Applied Clinical Medical Physics 2024年04月 [査読有り][通常論文]
  
• Impact of adaptive radiotherapy on survival in locally advanced nasopharyngeal carcinoma treated with concurrent chemoradiotherapy.

  Yusuke Uchinami, Koichi Yasuda, Hideki Minatogawa, Yasuhiro Dekura, Noboru Nishikawa, Rumiko Kinoshita, Kentaro Nishioka, Norio Katoh, Takashi Mori, Manami Otsuka, Naoki Miyamoto, Ryusuke Suzuki, Keiji Kobashi, Yasushi Shimizu, Jun Taguchi, Nayuta Tsushima, Satoshi Kano, Akihiro Homma, Hidefumi Aoyama

  Radiation oncology journal 42 1 74 - 82 2024年03月 

  PURPOSE: To investigate the clinical significance of adaptive radiotherapy (ART) in locally advanced nasopharyngeal carcinoma treated with intensity-modulated radiotherapy (IMRT). MATERIALS AND METHODS: Eligible patients were treated with concurrent chemoradiotherapy using IMRT. Planning computed tomography in ART was performed during radiotherapy, and replanning was performed. Since ART was started in May 2011 (ART group), patients who were treated without ART up to April 2011 (non-ART group) were used as the historical control. The Kaplan-Meier method was used to calculate overall survival (OS), locoregional recurrence-free survival (LRFS), progression-free survival (PFS), and distant metastasis-free survival (DMFS). LRFS for the primary tumor (LRFS_P) and regional lymph node (LRFS_LN) were also studied for more detailed analysis. Statistical significance was evaluated using the log-rank test for survival. RESULTS: The ART group tended to have higher radiation doses. The median follow-up period was 127 months (range, 10 to 211 months) in the non-ART group and 61.5 months (range, 5 to 129 months) in the ART group. Compared to the non-ART group, the ART group showed significantly higher 5-year PFS (53.8% vs. 81.3%, p = 0.015) and LRFS (61.2% vs. 85.3%, p = 0.024), but not OS (80.7% vs. 80.8%, p = 0.941) and DMFS (84.6% vs. 92.7%, p = 0.255). Five-year LRFS_P was higher in the ART group (61.3% vs. 90.6%, p = 0.005), but LRFS_LN did not show a significant difference (91.9% vs. 96.2%, p = 0.541). CONCLUSION: Although there were differences in the patient backgrounds between the two groups, this study suggests the potential effectiveness of ART in improving locoregional control, especially in the primary tumor.
• Real-time tumor-tracking radiotherapy with SyncTraX for primary liver tumors requiring isocenter shift†.

  Yusuke Uchinami, Naoki Miyamoto, Daisuke Abo, Ryo Morita, Koji Ogawa, Tatsuhiko Kakisaka, Ryusuke Suzuki, Tomohiko Miyazaki, Hiroshi Taguchi, Norio Katoh, Hidefumi Aoyama

  Journal of radiation research 65 1 92 - 99 2023年11月22日 [査読有り]
   

  The SyncTraX series enables real-time tumor-tracking radiotherapy through the real-time recognition of a fiducial marker using fluoroscopic images. In this system, the isocenter should be located within approximately 5-7.5 cm from the marker, depending on the version, owing to the limited field of view. If the marker is placed away from the tumor, the isocenter should be shifted toward the marker. This study aimed to investigate stereotactic body radiotherapy (SBRT) outcomes of primary liver tumors treated with SyncTraX in cases where the isocenter was shifted marginally or outside the planning target volume (PTV). Twelve patients with 13 liver tumors were included in the analysis. Their isocenter was shifted toward the marker and was placed marginally or outside the PTV. The prescribed doses were generally 40 Gy in four fractions or 48 Gy in eight fractions. The overall survival (OS) and local control (LC) rates were calculated using the Kaplan-Meier method. All patients completed the scheduled SBRT. The median distance between the fiducial marker and PTV centroid was 56.0 (interquartile range [IQR]: 52.7-66.7) mm. By shifting the isocenter toward the marker, the median distance between the marker and isocenter decreased to 34.0 (IQR: 33.4-39.7) mm. With a median follow-up period of 25.3 (range: 6.9-70.0) months, the 2-year OS and LC rates were 100.0% (95% confidence interval: 100-100). An isocenter shift makes SBRT with SyncTraX feasible in cases where the fiducial marker is distant from the tumor.
• Predicting the daily gastrointestinal doses of stereotactic body radiation therapy for pancreatic cancer based on the shortest distance between the tumor and the gastrointestinal tract using daily computed tomography images

  Yusuke Uchinami, Takahiro Kanehira, Keiji Nakazato, Yoshihiro Fujita, Fuki Koizumi, Shuhei Takahashi, Manami Otsuka, Koichi Yasuda, Hiroshi Taguchi, Kentaro Nishioka, Naoki Miyamoto, Kohei Yokokawa, Ryusuke Suzuki, Keiji Kobashi, Keita Takahashi, Norio Katoh, Hidefumi Aoyama

  BJR|Open 5 1 2023年08月 [査読有り]
   

  Objectives: We aimed to investigate whether daily computed tomography (CT) images could predict the daily gastroduodenal, small intestine, and large intestine doses of stereotactic body radiation therapy (SBRT) for pancreatic cancer based on the shortest distance between the gross tumor volume (GTV) and gastrointestinal (GI) tract. Methods: Twelve patients with pancreatic cancer received SBRT of 40 Gy in five fractions. We recalculated the reference clinical SBRT plan (PLAN_ref) using daily CT images and calculated the shortest distance from the GTV to each GI tract. The maximum dose delivered to 0.5 cc (D_0.5cc) was evaluated for each planning at-risk volume of the GI tract. Spearman’s correlation test was used to determine the association between the daily change in the shortest distance (Δshortest distance) and the ratio of ΔD_0.5cc dose to D_0.5cc dose in PLAN_ref (ΔD_0.5cc/PLAN_ref) for quantitative analysis. Results: The median shortest distance in PLAN_ref was 0 mm in the gastroduodenum (interquartile range, 0–2.7), 16.7 mm in the small intestine (10.0–23.7), and 16.7 mm in the large intestine (8.3–28.1 mm). The D_0.5cc of PLAN_ref in the gastroduodenum was >30 Gy in all patients, with 10 (83.3%) having the highest dose. A significant association was found between the Δshortest distance and ΔD_0.5cc/ PLAN_ref in the small or large intestine (p < 0.001) but not in the gastroduodenum (p = 0.404). Conclusions: The gastroduodenum had a higher D_0.5cc and predicting the daily dose was difficult. Daily dose calculations of the GI tract are recommended for safe SBRT. Advances in knowledge: This study aimed to predict the daily doses in SBRT for pancreatic cancer from the shortest distance between the GTV and the gastrointestinal tract. Daily changes in the shortest distance can predict the daily dose to the small or large intestines, but not to the gastroduodenum.
• Study of hepatic toxicity in small liver tumors after photon or proton therapy based on factors predicting the benefits of proton.

  Yusuke Uchinami, Norio Katoh, Daisuke Abo, Ryo Morita, Hiroshi Taguchi, Yoshihiro Fujita, Takahiro Kanehira, Ryusuke Suzuki, Naoki Miyamoto, Seishin Takao, Taeko Matsuura, Takuya Sho, Koji Ogawa, Tatsuya Orimo, Tatsuhiko Kakisaka, Keiji Kobashi, Hidefumi Aoyama

  The British journal of radiology 96 1144 20220720 - 20220720 2023年01月12日 [査読有り]
   

  OBJECTIVES: In a previous study of hepatic toxicity, the following three factors were identified to predict the benefits of proton beam therapy (PBT) for hepatocellular carcinomas (HCC) with a maximum diameter of ≤5 cm and Child-pugh grade A (CP-A): number of tumors (one vs ≥2), the location of tumors (hepatic hilum or others), and the sum of the diameters of lesions. The aim of this study is to analyze the association between these three factors and hepatic toxicity. METHODS: We retrospectively reviewed patients of CP-A treated with PBT or photon stereotactic body radiotherapy (X-ray radiotherapy, XRT) for HCC ≤5 cm. For normal liver dose, the V5, V10, V20 (volumes receiving 5, 10, and 20 Gy at least), and the mean dose was evaluated. The albumin-bilirubin (ALBI) and CP score changes from the baseline were evaluated at 3 and 6 months after treatment. RESULTS: In 89 patients (XRT: 48, PBT: 41), those with two or three (2-3) predictive factors were higher normal liver doses than with zero or one (0-1) factor. In the PBT group, the ALBI score worsened more in patients with 2-3 factors than those with 0-1 factor, at 3 months (median 0.26 vs 0.02, p = 0.032) and at 6 months (median: 0.35 vs 0.10, p = 0.009). The ALBI score change in the XRT group and CP score change in either modality were not significantly different in the number of predictive factors. CONCLUSIONS: The predictive factor numbers predicted the ALBI score change in PBT but not in XRT. ADVANCES IN KNOWLEDGE: This study suggest that the number of predictive factors previously identified (0-1 vs 2-3) were significantly associated with dosimetric parameters of the normal liver in both modalities. In the proton group, the number of predictive factors was associated with a worsening ALBI score at 3 and 6 months, but these associations were not found in the photon SBRT group.
• Detailed analysis of failure patterns using deformable image registration in hypopharyngeal cancer patients treated with sequential boost intensity-modulated radiotherapy.

  Manami Otsuka, Koichi Yasuda, Yusuke Uchinami, Nayuta Tsushima, Takayoshi Suzuki, Satoshi Kano, Ryusuke Suzuki, Naoki Miyamoto, Hideki Minatogawa, Yasuhiro Dekura, Takashi Mori, Kentaro Nishioka, Jun Taguchi, Yasushi Shimizu, Norio Katoh, Akihiro Homma, Hidefumi Aoyama

  Journal of medical imaging and radiation oncology 67 1 98 - 110 2022年11月14日 [査読有り]
   

  INTRODUCTION: Sequential boost intensity-modulated radiotherapy (SQB-IMRT) uses two different planning CTs (pCTs) and treatment plans. SQB-IMRT is a form of adaptive radiotherapy that allows for responses to changes in the shape of the tumour and organs at risk (OAR). On the other hand, dose accumulation with the two plans can be difficult to evaluate. The purpose of this study was to analyse patterns of loco-regional failure using deformable image registration (DIR) in hypopharyngeal cancer patients treated with SQB-IMRT. METHODS: Between 2013 and 2019, 102 patients with hypopharyngeal cancer were treated with definitive SQB-IMRT at our institution. Dose accumulation with the 1st and 2nd plans was performed, and the dose to the loco-regional recurrent tumour volume was calculated using the DIR workflow. Failure was classified as follows: (i) in-field (≥95% of the recurrent tumour volume received 95% of the prescribed dose); (ii) marginal (20-95%); or (iii) out-of-field (<20%). RESULTS: After a median follow-up period of 25 months, loco-regional failure occurred in 34 patients. Dose-volume histogram analysis showed that all loco-regional failures occurred in the field within 95% of the prescribed dose, with no marginal or out-of-field recurrences observed. CONCLUSION: The dosimetric analysis using DIR showed that all loco-regional failures were within the high-dose region. More aggressive treatment may be required for gross tumours.
• Multi-Institutional Study of End-to-End Dose Delivery Quality Assurance Testing for Image-Guided Brachytherapy Using a Gel Dosimeter.

  Hidenobu Tachibana, Yusuke Watanabe, Shogo Kurokawa, Takuya Maeyama, Tomoyuki Hiroki, Hideaki Ikoma, Hideaki Hirashima, Hironori Kojima, Takehiro Shiinoki, Yuuki Tanimoto, Hidetoshi Shimizu, Hiroki Shishido, Yoshitaka Oka, Taka-Aki Hirose, Masashi Kinjo, Takuya Morozumi, Masahiko Kurooka, Hidekazu Suzuki, Tomohiko Saito, Keiichi Fujita, Ryosuke Shirata, Ryuji Inada, Ryuichi Yada, Mikiko Yamashita, Kazuto Kondo, Takashi Hanada, Tadashi Takenaka, Keisuke Usui, Hiroyuki Okamoto, Hiroshi Asakura, Ryoichi Notake, Toru Kojima, Yu Kumazaki, Shogo Hatanaka, Riki Kikumura, Masaru Nakajima, Ryosei Nakada, Ryusuke Suzuki, Hideyuki Mizuno, Shinji Kawamura, Mistuhiro Nakamura, Tetsuo Akimoto

  Brachytherapy 21 6 956 - 967 2022年07月25日 [査読有り]
   

  PURPOSE: To quantify dose delivery errors for high-dose-rate image-guided brachytherapy (HDR-IGBT) using an independent end-to-end dose delivery quality assurance test at multiple institutions. The novelty of our study is that this is the first multi-institutional end-to-end dose delivery study in the world. MATERIALS AND METHODS: The postal audit used a polymer gel dosimeter in a cylindrical acrylic container for the afterloading system. Image acquisition using computed tomography, treatment planning, and irradiation were performed at each institution. Dose distribution comparison between the plan and gel measurement was performed. The percentage of pixels satisfying the absolute-dose gamma criterion was reviewed. RESULTS: Thirty-five institutions participated in this study. The dose uncertainty was 3.6% ± 2.3% (mean ± 1.96σ). The geometric uncertainty with a coverage factor of k = 2 was 3.5 mm. The tolerance level was set to the gamma passing rate of 95% with the agreement criterion of 5% (global)/3 mm, which was determined from the uncertainty estimation. The percentage of pixels satisfying the gamma criterion was 90.4% ± 32.2% (mean ± 1.96σ). Sixty-six percent (23/35) of the institutions passed the verification. Of the institutions that failed the verification, 75% (9/12) had incorrect inputs of the offset between the catheter tip and indexer length in treatment planning and 17% (2/12) had incorrect catheter reconstruction in treatment planning. CONCLUSIONS: The methodology should be useful for comprehensively checking the accuracy of HDR-IGBT dose delivery and credentialing clinical studies. The results of our study highlight the high risk of large source positional errors while delivering dose for HDR-IGBT in clinical practices.
• A study on predicting cases that would benefit from proton beam therapy in primary liver tumors of less than or equal to 5 cm based on the estimated incidence of hepatic toxicity

  Yusuke Uchinami, Norio Katoh, Ryusuke Suzuki, Takahiro Kanehira, Masaya Tamura, Seishin Takao, Taeko Matsuura, Naoki Miyamoto, Yoshihiro Fujita, Fuki Koizumi, Hiroshi Taguchi, Koichi Yasuda, Kentaro Nishioka, Isao Yokota, Keiji Kobashi, Hidefumi Aoyama

  Clinical and Translational Radiation Oncology 35 70 - 75 2022年07月 [査読有り]
  
• Treatment outcomes of stereotactic body radiation therapy using a real-time tumor-tracking radiotherapy system for hepatocellular carcinomas.

  Yusuke Uchinami, Norio Katoh, Daisuke Abo, Hiroshi Taguchi, Koichi Yasuda, Kentaro Nishioka, Takeshi Soyama, Ryo Morita, Naoki Miyamoto, Ryusuke Suzuki, Takuya Sho, Masato Nakai, Koji Ogawa, Tatsuhiko Kakisaka, Tatsuya Orimo, Toshiya Kamiyama, Shinichi Shimizu, Hidefumi Aoyama

  Hepatology research : the official journal of the Japan Society of Hepatology 51 8 870 - 879 2021年08月 [査読有り][通常論文]
   

  AIM: To report the outcomes of stereotactic body radiotherapy using a real-time tumor-tracking radiotherapy system for hepatocellular carcinoma patients. METHODS: From January 2005 to July 2018, 63 patients with 74 lesions with a maximum diameter ≤52 mm were treated by stereotactic body radiotherapy using a real-time tumor-tracking radiotherapy system. No patient with a Child-Pugh Score ≥9 was included, and 85.6% had a score of 5 or 6. Using the biological effective dose (BED) with an α/β ratio of 10 (BED10 ), the median dose in BED10 at the reference point was 76.8 Gy (range 60-122.5 Gy). Overall survival (OS) and local control rates were assessed using the Kaplan-Meier method. RESULTS: With a median follow-up period of 24.6 months (range 0.9-118.4 months), the 1-year and 2-year OS rates were 86.8% (95% confidence interval [95% CI] 75.8-93.3) and 71.1% (57.8-81.6), respectively. The 2-year OS was 89.6% in patients with the baseline modified albumin-bilirubin (mALBI) grade =1, and 61.7% in patients with grade ≥2a. In the multivariate analysis, the mALBI grade (=1 vs. ≥2a) was a significant factor for OS (p = 0.028, 95% CI 1.11-6.18). The 1-year and 2-year local control rates were 100% (100-100%) and 92.0% (77.5-97.5%). The local control rates were significantly higher in the BED10 ≥100 Gy group than in the BED10 <100 Gy group (2-year 100% vs. 86.5%, p = 0.049) at the reference point. CONCLUSION: This retrospective study of stereotactic body radiotherapy using real-time tumor-tracking radiotherapy for hepatocellular carcinoma showed favorable outcomes with lower incidence of toxicities, especially in patients treated with BED10 ≥100 Gy to the reference point.
• Fundamental study on quality assurance (QA) procedures for a real-time tumor tracking radiotherapy (RTRT) system from the viewpoint of imaging devices.

  Suguru Kimura, Naoki Miyamoto, Kenneth L Sutherland, Ryusuke Suzuki, Hiroki Shirato, Masayori Ishikawa

  Journal of applied clinical medical physics 22 7 165 - 176 2021年07月 [査読有り]
   

  PURPOSE: The real-time tumor tracking radiotherapy (RTRT) system requires periodic quality assurance (QA) and quality control. The goal of this study is to propose QA procedures from the viewpoint of imaging devices in the RTRT system. METHODS: Tracking by the RTRT system (equips two sets of colored image intensifiers (colored I.I.s) fluoroscopy units) for the moving gold-marker (diameter 2.0 mm) in a rotating phantom were performed under various X-ray conditions. To analyze the relationship between fluoroscopic image quality and precision of gold marker coordinate calculation, the standard deviation of the 3D coordinate (σ3D [mm]) of the gold marker, the mean of the pattern recognition score (PRS) and the standard deviation of the distance between rays (DBR) (σDBR [mm]) were evaluated. RESULTS: When tracking with speed of 10-60 mm/s, σDBR increased, though the mean PRS did not change significantly (p>0.05). On the contrary, the mean PRS increased depending on the integral noise equivalent quanta (∫NEQ) that is an indicator of image quality calculated from the modulation transfer function (MTF) as an indicator of spatial resolution and the noise power spectrum (NPS) as an indicator of noise characteristic. CONCLUSION: The indicators of NEQ, MTF, and NPS were useful for managing the tracking accuracy of the RTRT system. We propose observing the change of these indicators as additional QA procedures for each imaging device from the commissioning baseline.
• Potential benefits of adaptive intensity-modulated proton therapy in nasopharyngeal carcinomas.

  Hideki Minatogawa, Koichi Yasuda, Yasuhiro Dekura, Seishin Takao, Taeko Matsuura, Takaaki Yoshimura, Ryusuke Suzuki, Isao Yokota, Noriyuki Fujima, Rikiya Onimaru, Shinichi Shimizu, Hidefumi Aoyama, Hiroki Shirato

  Journal of applied clinical medical physics 22 1 174 - 183 2021年01月 [査読有り]
   

  PURPOSE: To investigate potential advantages of adaptive intensity-modulated proton beam therapy (A-IMPT) by comparing it to adaptive intensity-modulated X-ray therapy (A-IMXT) for nasopharyngeal carcinomas (NPC). METHODS: Ten patients with NPC treated with A-IMXT (step and shoot approach) and concomitant chemotherapy between 2014 and 2016 were selected. In the actual treatment, 46 Gy in 23 fractions (46Gy/23Fx.) was prescribed using the initial plan and 24Gy/12Fx was prescribed using an adapted plan thereafter. New treatment planning of A-IMPT was made for the same patients using equivalent dose fractionation schedule and dose constraints. The dose volume statistics based on deformable images and dose accumulation was used in the comparison of A-IMXT with A-IMPT. RESULTS: The means of the Dmean of the right parotid gland (P < 0.001), right TM joint (P < 0.001), left TM joint (P < 0.001), oral cavity (P < 0.001), supraglottic larynx (P = 0.001), glottic larynx (P < 0.001), , middle PCM (P = 0.0371), interior PCM (P < 0.001), cricopharyngeal muscle (P = 0.03643), and thyroid gland (P = 0.00216), in A-IMPT are lower than those of A-IMXT, with statistical significance. The means of, D0.03cc , and Dmean of each sub portion of auditory apparatus and D30% for Eustachian tube and D0.5cc for mastoid volume in A-IMPT are significantly lower than those of A-IMXT. The mean doses to the oral cavity, supraglottic larynx, and glottic larynx were all reduced by more than 20 Gy (RBE = 1.1). CONCLUSIONS: An adaptive approach is suggested to enhance the potential benefit of IMPT compared to IMXT to reduce adverse effects for patients with NPC.
• An overview of the medical-physics-related verification system for radiotherapy multicenter clinical trials by the Medical Physics Working Group in the Japan Clinical Oncology Group-Radiation Therapy Study Group.

  Teiji Nishio, Mitsuhiro Nakamura, Hiroyuki Okamoto, Satoshi Kito, Toshiyuki Minemura, Shuichi Ozawa, Yu Kumazaki, Masayori Ishikawa, Naoki Tohyama, Masahiko Kurooka, Takeo Nakashima, Hidetoshi Shimizu, Ryusuke Suzuki, Satoshi Ishikura, Yasumasa Nishimura

  Journal of radiation research 61 6 999 - 1008 2020年11月16日 [査読有り]
   

  The Japan Clinical Oncology Group-Radiation Therapy Study Group (JCOG-RTSG) has initiated several multicenter clinical trials for high-precision radiotherapy, which are presently ongoing. When conducting multi-center clinical trials, a large difference in physical quantities, such as the absolute doses to the target and the organ at risk, as well as the irradiation localization accuracy, affects the treatment outcome. Therefore, the differences in the various physical quantities used in different institutions must be within an acceptable range for conducting multicenter clinical trials, and this must be verified with medical physics consideration. In 2011, Japan's first Medical Physics Working Group (MPWG) in the JCOG-RTSG was established to perform this medical-physics-related verification for multicenter clinical trials. We have developed an auditing method to verify the accuracy of the absolute dose and the irradiation localization. Subsequently, we credentialed the participating institutions in the JCOG multicenter clinical trials that were using stereotactic body radiotherapy (SBRT) for lungs, intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) for several disease sites, and proton beam therapy (PT) for the liver. From the verification results, accuracies of the absolute dose and the irradiation localization among the participating institutions of the multicenter clinical trial were assured, and the JCOG clinical trials could be initiated.
• The urethral position may shift due to urethral catheter placement in the treatment planning for prostate radiation therapy.

  Yasuhiro Dekura, Kentaro Nishioka, Takayuki Hashimoto, Naoki Miyamoto, Ryusuke Suzuki, Takaaki Yoshimura, Ryuji Matsumoto, Takahiro Osawa, Takashige Abe, Yoichi M Ito, Nobuo Shinohara, Hiroki Shirato, Shinichi Shimizu

  Radiation oncology (London, England) 14 1 226 - 226 2019年12月12日 [査読有り][通常論文]
   

  PURPOSE: To determine the best method to contour the planning organ at risk volume (PRV) for the urethra, this study aimed to investigate the displacement of a Foley catheter in the urethra with a soft and thin guide-wire. METHODS: For each patient, the study used two sets of computed tomography (CT) images for radiation treatment planning (RT-CT): (1) set with a Foley urethral catheter (4.0 mm diameter) plus a guide-wire (0.46 mm diameter) in the first RT-CT and (2) set with a guide-wire alone in the second CT recorded 2 min after the first RT-CT. Using three fiducial markers in the prostate for image fusion, the displacement between the catheter and the guide-wire in the prostatic urethra was calculated. In 155 consecutive patients treated between 2011 and 2017, 5531 slices of RT-CT were evaluated. RESULTS: Assuming that ≥3.0 mm of difference between the catheter and the guide-wire position was a significant displacement, the urethra with the catheter was displaced significantly from the urethra with the guide-wire alone in > 20% of the RT-CT slices in 23.2% (36/155) of the patients. The number of patients who showed ≥3.0 mm anterior displacement with the catheter in ≥20% RT-CT slices was significantly larger at the superior segment (38/155) than at the middle (14/155) and inferior segments (18/155) of the prostatic urethra (p < 0.0167). CONCLUSIONS: The urethral position with a Foley catheter is different from the urethral position with a thin and soft guide-wire in a significant proportion of the patients. This should be taken into account for the PRV of the urethra to ensure precise radiotherapy such as in urethra-sparing radiotherapy.
• The Potential Benefit of Adaptive Intensity Modulated Proton Therapy in Nasopharyngeal Carcinoma: Planning Comparison Study

  H. Minatogawa, K. Yasuda, T. Matsuura, R. Onimaru, T. Yoshimura, S. Takao, Y. Matsuo, Y. Dekura, R. Suzuki, M. Tamura, N. Miyamoto, S. Shimizu, H. Shirato

  International Journal of Radiation Oncology*Biology*Physics 105 1 E394 - E394 2019年09月
• Impact of organ motion on volumetric and dosimetric parameters in stomach lymphomas treated with intensity-modulated radiotherapy.

  Uchinami Y, Suzuki R, Katoh N, Taguchi H, Yasuda K, Miyamoto N, Ito YM, Shimizu S, Shirato H

  Journal of applied clinical medical physics 20 8 78 - 86 2019年08月 [査読有り][通常論文]
   

  PURPOSE: Interplay effects may influence dose distributions to a moving target when using dynamic delivery techniques such as intensity-modulated radiotherapy (IMRT). The aim of this study was to evaluate the impact of organ motion on volumetric and dosimetric parameters in stomach lymphomas treated with IMRT. METHODS: Ten patients who had been treated with IMRT for stomach lymphomas were enrolled. The clinical target volume (CTV) was contoured as the whole stomach. Considering interfractional uncertainty, the internal target volume (ITV) margin was uniformly 1.5 cm to the CTV and then modified based on the 4DCT images in case of the large respiratory motion. The planning target volume (PTV) was created by adding 5 mm to the ITV. The impact of organ motion on the volumetric and dosimetric parameters was evaluated retrospectively (4D simulation). The organ motion was reproduced by shifting the isocenter on the radiation treatment planning system. Several simulation plans were created to test the influence of the beam-on timing in the respiration cycle on the dose distribution. The homogeneity index (HI), volume percentage of stomach covered by the prescribed dose (Vp ), and D99 of the CTV were evaluated. RESULTS: The organ motion was the largest in the superior-inferior direction (10.1 ± 4.5 mm [average ± SD]). Stomach volume in each respiratory phase compared to the mean volume varied approximately within a ± 5% range in most of the patients. The PTV margin was sufficiently large to cover the CTV during the IMRT. There was a significant reduction in Vp and D99 but not in HI in the 4D simulation in free-breathing and multiple fractions compared to the clinically-used plan (P < 0.05) suggesting that interplay effects deteriorate the dose distribution. The absolute difference of D99 was less than 1% of the prescribed dose. CONCLUSIONS: There were significant interplay effects affecting the dose distribution in stomach IMRT. The magnitude of the dose reduction was small when patients were treated on free-breathing and multiple fractions.
• 強度変調放射線治療中に皮下気腫をきたし,再検証を要した頭頸部癌患者の1例

  湊川 英樹, 安田 耕一, 白土 博樹, 土屋 和彦, 鈴木 隆介, 宮本 直樹, 坂下 智博, 本間 明宏, 福田 諭

  Japanese Journal of Radiology 37 Suppl. 4 - 4 (公社)日本医学放射線学会 2019年02月
• 北海道大学病院医学物理部の紹介

  Ryusuke Suzuki, Naoki Miyamoto, Seishin Takao, Shinichi Shimizu

  医学物理 39 2 54 - 56 2019年
• Determination of the urethra position for accurate radiation therapy of prostate cancers

  Dekura Yasuhiro, Nishioka Kentaro, Hashimoto Takayuki, Miyamoto Naoki, Suzuki Ryusuke, Matsumoto Ryuji, Osawa Takahiro, Abe Takashige, Maruyama Satoru, Shinohara Nobuo, Shirato Hiroki, Shimizu Shinichi

  INTERNATIONAL JOURNAL OF UROLOGY 25 445 - 445 2018年10月 [査読有り][通常論文]
  
• 同時期に異所性に発生した悪性腫瘍に対して、二部位同時にIMRTを施行した症例

  湊川 英樹, 安田 耕一, 白土 博樹, 土屋 和彦, 原田 八重, 水町 貴諭, 坂下 智博, 本間 明宏, 福田 諭, 石嶋 漢, 宮本 直樹, 高尾 聖心, 鈴木 隆介, 松浦 妙子, 牧永 綾乃, 田村 昌也

  Japanese Journal of Radiology 36 Suppl. 6 - 6 (公社)日本医学放射線学会 2018年02月
• Lifetime attributable risk of radiation-induced secondary cancer from proton beam therapy compared with that of intensity-modulated X-ray therapy in randomly sampled pediatric cancer patients

  Masaya Tamura, Hideyuki Sakurai, Masashi Mizumoto, Satoshi Kamizawa, Shigeyuki Murayama, Haruo Yamashita, Seishin Takao, Ryusuke Suzuki, Hiroki Shirato, Yoichi M. Ito

  JOURNAL OF RADIATION RESEARCH 58 3 363 - 371 2017年05月 [査読有り][通常論文]
   

  To investigate the amount that radiation-induced secondary cancer would be reduced by using proton beam therapy (PBT) in place of intensity-modulated X-ray therapy (IMXT) in pediatric patients, we analyzed lifetime attributable risk (LAR) as an in silico surrogate marker of the secondary cancer after these treatments. From 242 pediatric patients with cancers who were treated with PBT, 26 patients were selected by random sampling after stratification into four categories: (i) brain, head and neck, (ii) thoracic, (iii) abdominal, and (iv) whole craniospinal (WCNS) irradiation. IMXT was replanned using the same computed tomography and region of interest. Using the dose-volume histograms (DVHs) of PBT and IMXT, the LARs of Schneider et al. were calculated for the same patient. All the published dose-response models were tested for the organs at risk. Calculation of the LARs of PBT and IMXT based on the DVHs was feasible for all patients. The means +/- standard deviations of the cumulative LAR difference between PBT and IMXT for the four categories were (i) 1.02 +/- 0.52% (n = 7, P = 0.0021), (ii) 23.3 +/- 17.2% (n = 8, P = 0.0065), (iii) 16.6 +/- 19.9% (n = 8, P = 0.0497) and (iv) 50.0 +/- 21.1% (n = 3, P = 0.0274), respectively (one tailed t-test). The numbers needed to treat (NNT) were (i) 98.0, (ii) 4.3, (iii) 6.0 and (iv) 2.0 for WCNS, respectively. In pediatric patients who had undergone PBT, the LAR of PBT was significantly lower than the LAR of IMXT estimated by in silico modeling. Although a validation study is required, it is suggested that the LAR would be useful as an in silico surrogate marker of secondary cancer induced by different radiotherapy techniques.
• Lifetime attributable risk of radiation-induced secondary cancer from proton beam therapy compared with that of intensity-modulated X-ray therapy in randomly sampled pediatric cancer patients

  Tamura,Masaya, Sakurai,Hideyuki, Mizumoto,Masashi, Kamizawa,Satoshi, Murayama,Shigeyuki, Yamashita,Haruo, Takao,Seishin, Suzuki,Ryusuke, Shirato,Hiroki, Ito,M. Yoichi

  J Radiat Res 58 3 363 - 371 OXFORD UNIV PRESS 2016年10月 [査読有り][通常論文]
   

  To investigate the amount that radiation-induced secondary cancer would be reduced by using proton beam therapy (PBT) in place of intensity-modulated X-ray therapy (IMXT) in pediatric patients, we analyzed lifetime attributable risk (LAR) as an in silico surrogate marker of the secondary cancer after these treatments. From 242 pediatric patients with cancers who were treated with PBT, 26 patients were selected by random sampling after stratification into four categories: (i) brain, head and neck, (ii) thoracic, (iii) abdominal, and (iv) whole craniospinal (WCNS) irradiation. IMXT was replanned using the same computed tomography and region of interest. Using the dose-volume histograms (DVHs) of PBT and IMXT, the LARs of Schneider et al were calculated for the same patient. All the published dose-response models were tested for the organs at risk. Calculation of the LARs of PBT and IMXT based on the DVHs was feasible for all patients. The means ± standard deviations of the cumulative LAR difference between PBT and IMXT for the four categories were (i) 1.02 ± 0.52% (n = 7, P = 0.0021), (ii) 23.3 ± 17.2% (n = 8, P = 0.0065), (iii) 16.6 ± 19.9% (n = 8, P = 0.0497)
• NTCP modeling analysis of acute hematologic toxicity in whole pelvic radiation therapy for gynecologic malignancies - A dosimetric comparison of IMRT and spot-scanning proton therapy (SSPT)

  Takaaki Yoshimura, Rumiko Kinoshita, Shunsuke Onodera, Chie Toramatsu, Ryusuke Suzuki, Yoichi M. Ito, Seishin Takao, Taeko Matsuura, Yuka Matsuzaki, Kikuo Umegaki, Hiroki Shirato, Shinichi Shimizu

  PHYSICA MEDICA-EUROPEAN JOURNAL OF MEDICAL PHYSICS 32 9 1095 - 1102 2016年09月 [査読有り][通常論文]
   

  Purpose: This treatment planning study was conducted to determine whether spot scanning proton beam therapy (SSPT) reduces the risk of grade >= 3 hematologic toxicity (HT3+) compared with intensity modulated radiation therapy (IMRT) for postoperative whole pelvic radiation therapy (WPRT). Methods and materials: The normal tissue complication probability (NTCP) of the risk of HT3+ was used as an in silico surrogate marker in this analysis. IMRT and SSPT plans were created for 13 gynecologic malignancy patients who had received hysterectomies. The IMRT plans were generated using the 7-fields step and shoot technique. The SSPT plans were generated using anterior-posterior field with single field optimization. Using the relative biological effectives (RBE) value of 1.0 for IMRT and 1.1 for SSPT, the prescribed dose was 45 Gy(RBE) in 1.8 Gy(RBE) per fractions for 95% of the planning target volume (PTV). The homogeneity index (HI) and the conformity index (CI) of the PTV were also compared. Results: The bone marrow (BM) and femoral head doses using SSPT were significantly lower than with IMRT. The NTCP modeling analysis showed that the risk of HT3+ using SSPT was significantly lower than with IMRT (NTCP = 0.04 +/- 0.01 and 0.19 +/- 0.03, p = 0.0002, respectively). There were no significant differences in the CI and HI of the PTV between IMRT and SSPT (CI = 0.97 +/- 0.01 and 0.96 +/- 0.02, p = 0.3177, and HI = 1.24 +/- 0.11 and 1.27 +/- 0.05, p = 0.8473, respectively). Conclusion: The SSPT achieves significant reductions in the dose to BM without compromising target coverage, compared with IMRT. The NTCP value for HT3+ in SSPT was significantly lower than in IMRT. (C) 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.
• 照射中と4DCT撮像時の肺内マーカー移動の比較

  原田慶一, 加藤徳雄, 井上哲也, 鬼丸力也, 清水伸一, 白土博樹, 鈴木隆介, 宮本直樹, 石川正純

  Japanese Journal of Radiology 34 Supplement 10 - 10 (公社)日本医学放射線学会 2016年02月25日 [査読無し][通常論文]
  
• Evaluation of the motion of lung tumors during stereotactic body radiation therapy (SBRT) with four-dimensional computed tomography (4DCT) using real-time tumor-tracking radiotherapy system (RTRT)

  Keiichi Harada, Norio Katoh, Ryusuke Suzuki, Yoichi M. Ito, Shinichi Shimizu, Rikiya Onimaru, Tetsuya Inoue, Naoki Miyamoto, Hiroki Shirato

  PHYSICA MEDICA-EUROPEAN JOURNAL OF MEDICAL PHYSICS 32 2 305 - 311 2016年02月 [査読有り][通常論文]
   

  Purpose: We investigated the usefulness of four-dimensional computed tomography (4DCT) performed before stereotactic body radiation therapy (SBRT) in determining the internal margins for peripheral lung tumors. Methods and Materials: The amplitude of the movement of a fiducial marker near a lung tumor measured using the maximum intensity projection (MIP) method in 4DCT imaging was acquired before the SBRT (Amp(CT)) and compared with the mean amplitude of the marker movement during SBRT (Amp(mean)) and with the maximum amplitude of the marker movement during SBRT (Amp(max)) using a real-time tumortracking radiotherapy (RTRT) system with 22 patients. Results: There were no significant differences between the means of the Amp(mean) and the means of the Amp(CT) in all directions (LR, P = 0.45; CC, P = 0.80; AP, P = 0.65). The means of the Amp(max) were significantly larger than the means of the Amp(CT) in all directions (LR, P < 0.01; CC, P = 0.03; AP, P < 0.01). In the lower lobe, the mean difference of the Amp(CT) from the mean of the Amp(max) was 5.7 +/- 8.0 mm, 12.5 +/- 16.7 mm, and 6.8 +/- 8.5 mm in the LR, CC, and AP directions, respectively. Conclusions: Acquiring 4DCT MIP images before the SBRT treatment is useful to establish the mean amplitude for a patient during SBRT but it underestimates the maximum amplitude during actual SBRT. Caution must be paid to determine the margin with the 4DCT especially for tumors at the lower lobe where it is of the potentially greatest benefit. (C) 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd.
• 呼吸性移動の複雑さと対策:最新の動体追跡放射線治療

  宮本直樹, 高尾聖心, 原田慶一, 石川正純, 鈴木隆介, 松浦妙子, 牧永彩乃, 井上哲也, 加藤徳雄, 清水伸一, 鬼丸力也, 白土博樹

  日本放射線腫瘍学会高精度放射線外部照射部会学術大会プログラム・抄録集 29th 46  2016年 [査読無し][通常論文]
  
• Intrafractional Baseline Shift or Drift of Lung Tumor Motion During Gated Radiation Therapy With a Real-Time Tumor-Tracking System

  Seishin Takao, Naoki Miyamoto, Taeko Matsuura, Rikiya Onimaru, Norio Katoh, Tetsuya Inoue, Kenneth Lee Sutherland, Ryusuke Suzuki, Hiroki Shirato, Shinichi Shimizu

  INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS 94 1 172 - 180 2016年01月 [査読有り][通常論文]
   

  Purpose: To investigate the frequency and amplitude of baseline shift or drift (shift/drift) of lung tumors in stereotactic body radiation therapy (SBRT), using a real-time tumor-tracking radiation therapy (RTRT) system. Methods and Materials: Sixty-eight patients with peripheral lung tumors were treated with SBRT using the RTRT system. One of the fiducial markers implanted near the tumor was used for the real-time monitoring of the intrafractional tumor motion every 0.033 seconds by the RTRT system. When baseline shift/drift is determined by the system, the position of the treatment couch is adjusted to compensate for the shift/drift. Therefore, the changes in the couch position correspond to the baseline shift/drift in the tumor motion. The frequency and amount of adjustment to the couch positions in the left-right (LR), cranio-caudal (CC), and antero-posterior (AP) directions have been analyzed for 335 fractions administered to 68 patients. Results: The average change in position of the treatment couch during the treatment time was 0.45 +/- 2.23 mm (mean +/- standard deviation), -1.65 +/- 5.95 mm, and 1.50 +/- 2.54 mm in the LR, CC, and AP directions, respectively. Overall the baseline shift/drift occurs toward the cranial and posterior directions. The incidence of baseline shift/drift exceeding 3 mm was 6.0%, 15.5%, 14.0%, and 42.1% for the LR, CC, AP, and for the square-root of sum of 3 directions, respectively, within 10 minutes of the start of treatment, and 23.0%, 37.6%, 32.5%, and 71.6% within 30 minutes. Conclusions: Real-time monitoring and frequent adjustments of the couch position and/or adding appropriate margins are suggested to be essential to compensate for possible underdosages due to baseline shift/drift in SBRT for lung cancers. (C) 2016 Elsevier Inc. All rights reserved.
• Development of a wavelength-separated type scintillator with optical fiber (SOF) dosimeter to compensate for the Cerenkov radiation effect

  Masayori Ishikawa, Naomi Nagase, Taeko Matsuura, Junichi Hiratsuka, Ryusuke Suzuki, Naoki Miyamoto, Kenneth Lee Sutherland, Katsuhisa Fujita, Hiroki Shirato

  JOURNAL OF RADIATION RESEARCH 56 2 372 - 381 2015年03月 [査読有り][通常論文]
   

  The scintillator with optical fiber (SOF) dosimeter consists of a miniature scintillator mounted on the tip of an optical fiber. The scintillator of the current SOF dosimeter is a 1-mm diameter hemisphere. For a scintillation dosimeter coupled with an optical fiber, measurement accuracy is influenced by signals due to Cerenkov radiation in the optical fiber. We have implemented a spectral filtering technique for compensating for the Cerenkov radiation effect specifically for our plastic scintillator-based dosimeter, using a wavelength-separated counting method. A dichroic mirror was used for separating input light signals. Individual signal counting was performed for high-and low-wavelength light signals. To confirm the accuracy, measurements with various amounts of Cerenkov radiation were performed by changing the incident direction while keeping the Ir-192 source-to-dosimeter distance constant, resulting in a fluctuation of <5%. Optical fiber bending was also addressed; no bending effect was observed for our wavelength-separated SOF dosimeter.
• 4DCTを用いた肺内マーカー移動の解析

  加藤徳雄, 原田慶一, 鈴木隆介, 井上哲也, 鬼丸力也, 清水伸一, 宮本直樹, 白土博樹

  Jpn J Radiol 33 Supplement 5 - 5 (公社)日本医学放射線学会 2015年02月25日 [査読無し][通常論文]
  
• A motion-compensated image filter for low-dose fluoroscopy in a real-time tumor-tracking radiotherapy system

  Naoki Miyamoto, Masayori Ishikawa, Kenneth Sutherland, Ryusuke Suzuki, Taeko Matsuura, Chie Toramatsu, Seishin Takao, Hideaki Nihongi, Shinichi Shimizu, Kikuo Umegaki, Hiroki Shirato

  JOURNAL OF RADIATION RESEARCH 56 1 186 - 196 2015年01月 [査読有り][通常論文]
   

  In the real-time tumor-tracking radiotherapy system, a surrogate fiducial marker inserted in or near the tumor is detected by fluoroscopy to realize respiratory-gated radiotherapy. The imaging dose caused by fluoroscopy should be minimized. In this work, an image processing technique is proposed for tracing a moving marker in low-dose imaging. The proposed tracking technique is a combination of a motion-compensated recursive filter and template pattern matching. The proposed image filter can reduce motion artifacts resulting from the recursive process based on the determination of the region of interest for the next frame according to the current marker position in the fluoroscopic images. The effectiveness of the proposed technique and the expected clinical benefit were examined by phantom experimental studies with actual tumor trajectories generated from clinical patient data. It was demonstrated that the marker motion could be traced in low-dose imaging by applying the proposed algorithm with acceptable registration error and high pattern recognition score in all trajectories, although some trajectories were not able to be tracked with the conventional spatial filters or without image filters. The positional accuracy is expected to be kept within +/- 2 mm. The total computation time required to determine the marker position is a few milliseconds. The proposed image processing technique is applicable for imaging dose reduction.
• 局所進行食道癌に対する強度変調放射線治療を用いた放射線化学療法の経験

  井上哲也, 加藤徳雄, 清水伸一, 白土博樹, 鈴木隆介, 佐々木尚英, 福島拓, 小松嘉人

  北海道外科雑誌 59 2 206 - 206 北海道外科学会 2014年12月20日 [査読無し][通常論文]
  
• Towards a More Complete and Accurate Experimental Nuclear Reaction Data Library (EXFOR): International Collaboration Between Nuclear Reaction Data Centres (NRDC)

  N. Otuka, E. Dupont, V. Semkova, B. Pritychenko, A. I. Blokhin, M. Aikawa, S. Babykina, M. Bossant, G. Chen, S. Dunaeva, R. A. Forrest, T. Fukahori, N. Furutachi, S. Ganesan, Z. Ge, O. O. Gritzay, M. Herman, S. Hlavac, K. Kato, B. Lalremruata, Y. O. Lee, A. Makinaga, K. Matsumoto, M. Mikhaylyukova, G. Pikulina, V. G. Pronyaev, A. Saxena, O. Schwerer, S. P. Simakov, N. Soppera, R. Suzuki, S. Takacs, X. Tao, S. Taova, F. Tarkanyi, V. V. Varlamov, J. Wang, S. C. Yang, V. Zerkin, Y. Zhuang

  NUCLEAR DATA SHEETS 120 272 - 276 2014年06月 [査読有り][通常論文]
   

  The International Network of Nuclear Reaction Data Centres (NRDC) coordinated by the IAEA Nuclear Data Section (NDS) successfully collaborates in the maintenance and development of the EXFOR library. As the scope of published data expands (e.g. to higher energy, to heavier projectile) to meet the needs of research and applications, it has become a challenging task to maintain both the completeness and accuracy of the EXFOR library. Evolution of the library highlighting recent developments is described.
• Early results of urethral dose reduction and small safety margin in intensity-modulated radiation therapy (IMRT) for localized prostate cancer using a real-time tumor-tracking radiotherapy (RTRT) system

  Shinichi Shimizu, Kentaro Nishioka, Ryusuke Suzuki, Nobuo Shinohara, Satoru Maruyama, Takashige Abe, Rumiko Kinoshita, Norio Katoh, Rikiya Onimaru, Hiroki Shirato

  RADIATION ONCOLOGY 9 118  2014年05月 [査読有り][通常論文]
   

  Background: We prospectively assessed the utility of intensity-modulated radiation therapy (IMRT) with urethral dose reduction and a small margin between the clinical target volume (CTV) and the planning target volume (PTV) for patients with localized prostate cancer. Methods: The study population was 110 patients in low- (14.5%), intermediate- (41.8%), and high-risk (43.6%) categories. Three gold fiducial markers were inserted into the prostate. A soft guide-wire was used to identify the urethra when computed tomography (CT) scan for treatment planning was performed. A dose constraint of V70 < 10% was applied to the urethral region. Margins between the CTV-PTV were set at 3 mm in all directions. Patients were treated with 70 Gy IMRT in 30 fractions (D95 of PTV) over 7.5 weeks. The patient couch was adjusted to keep the gold markers within 2.0 mm from their planned positions with the use of frequent on-line verification. Results: The median follow-up period was 31.3 (3.2 to 82.1) months. The biochemical relapse-free survival (bRFS) rates at 3 years were 100%, 93.8% and 89.5% for the low-, intermediate-, and high-risk patients, respectively. The incidences of acute adverse events (AEs) were 45.5% and 0.9% for grades 1 and 2, respectively. The late AEs were grade 1 cystitis in 10.0% of the patients, rectal bleeding in 7.3%, and urinary urgency in 6.4%. Only three patients (2.7%) developed grade 2 late AEs. Conclusions: On-line image guidance with precise correction of the table position during radiotherapy achieved one of the lowest AEs rates with a bRFS equal to the highest in the literature.
• 放射線治療に関する名称付けルール

  安田耕一, 土屋和彦, 井上哲也, 西岡健太郎, 原田慶一, 西川由記子, 鬼丸力也, 清水伸一, 加藤徳雄, 木下留美子, 小野寺俊介, 白土博樹, 鈴木隆介, 藤田勝久, 辻真太郎, 山崎理衣

  Jpn J Radiol 32 Supplement 7 - 7 (公社)日本医学放射線学会 2014年02月25日 [査読無し][通常論文]
  
• 北海道大学病院における髄膜腫に対する強度変調放射線治療(IMRT)の初期成績

  西川由記子, 原田慶一, 西岡健太郎, 安田耕一, 井上哲也, 土屋和彦, 小野寺俊輔, 木下留美子, 加藤徳雄, 清水伸一, 鬼丸力也, 白土博樹, 鈴木隆介, 石川正純

  Jpn J Radiol 32 Supplement 5 - 5 (公社)日本医学放射線学会 2014年02月25日 [査読無し][通常論文]
  
• Dosimetric comparison between intensity-modulated radiotherapy and standard wedged tangential technique for whole-breast radiotherapy in Asian women with relatively small breast volumes

  Kazuhiko Tsuchiya, Rumiko Kinoshita, Shinichi Shimizu, Kentaro Nishioka, Keiichi Harada, Noboru Nishikawa, Ryusuke Suzuki, Hiroki Shirato

  Radiological Physics and Technology 7 1 67 - 72 2014年 [査読有り][通常論文]
   

  We sought to investigate whether intensity-modulated radiotherapy (IMRT) has a dosimetric advantage compared to the standard wedged tangential technique (SWT) for whole-breast radiotherapy (WBRT) in Asian women with relatively small breast volume. Computed tomography images of 25 Asian patients with early-stage breast cancer (right 15, left 10) used for WBRT planning were examined. After contouring the target volumes and bilateral lungs and, for left-side treatment, the heart, 4 plans were made for each patient: namely, SWT, tangential-field IMRT (T-IMRT), 3-field IMRT (3F-IMRT), and 4-field IMRT (4F-IMRT). The prescribed dose was 5000 cGy. The median planning target volume (PTV) for WBRT was 552.6 cc (range 288.8-1518.4 cc). Compared to SWT, (1) T-IMRT achieved significant improvement for dose homogeneity in the PTV (p < 0.001) and the dose received by 2 % (D2) of the PTV (p < 0.001). T-IMRT also reduced the bilateral lung mean dose (p < 0.001) and the ipsilateral lung volume which received more than 20 Gy (V20) (p = 0.01). (2) 3F-IMRT resulted in a significant increase in the mean dose to the ipsilateral lung (p < 0.001) and to the contralateral lung (p < 0.001). (3) 4F-IMRT also resulted in a significant increase in the mean dose to the ipsilateral lung (p < 0.001) and to the contralateral lung (p < 0.001). Tangential-field IMRT provided an improved dose distribution compared with SWT for WBRT in Asian women with a relatively small breast volume. © Japanese Society of Radiological Technology and Japan Society of Medical Physics 2013.
• 局所進行食道癌に対する通常照射と強度変調放射線治療を組み合わせた放射線化学療法

  井上哲也, 加藤徳雄, 清水伸一, 白土博樹, 鈴木隆介, 佐々木尚英, 福島拓, 小松嘉人

  北海道外科雑誌 58 2 112 - 216 北海道外科学会 2013年12月20日 [査読無し][通常論文]
  
• 医療情報誘導治療の最新 リアルタイム4次元放射線治療の―スーパー特区の成果―

  白土博樹, 鬼丸力也, 清水伸一, 石川正純, 宮本直樹, SUTHERLAND Ken, 鈴木隆介, 寅松千枝

  映像情報Medical 45 7 619 - 623 産業開発機構 2013年07月01日 [査読無し][通常論文]
  
• Integration of a real-time tumor monitoring system into gated proton spot-scanning beam therapy: An initial phantom study using patient tumor trajectory data

  Taeko Matsuura, Naoki Miyamoto, Shinichi Shimizu, Yusuke Fujii, Masumi Umezawa, Seishin Takao, Hideaki Nihongi, Chie Toramatsu, Kenneth Sutherland, Ryusuke Suzuki, Masayori Ishikawa, Rumiko Kinoshita, Kenichiro Maeda, Kikuo Umegaki, Hiroki Shirato

  MEDICAL PHYSICS 40 7 071729  2013年07月 [査読有り][通常論文]
   

  Purpose: In spot-scanning proton therapy, the interplay effect between tumor motion and beam delivery leads to deterioration of the dose distribution. To mitigate the impact of tumor motion, gating in combination with repainting is one of the most promising methods that have been proposed. This study focused on a synchrotron-based spot-scanning proton therapy system integrated with real-time tumor monitoring. The authors investigated the effectiveness of gating in terms of both the delivered dose distribution and irradiation time by conducting simulations with patients' motion data. The clinically acceptable range of adjustable irradiation control parameters was explored. Also, the relation between the dose error and the characteristics of tumor motion was investigated. Methods: A simulation study was performed using a water phantom. A gated proton beam was irradiated to a clinical target volume (CTV) of 5 x 5 x 5 cm(3), in synchronization with lung cancer patients' tumor trajectory data. With varying parameters of gate width, spot spacing, and delivered dose per spot at one time, both dose uniformity and irradiation time were calculated for 397 tumor trajectory data from 78 patients. In addition, the authors placed an energy absorber upstream of the phantom and varied the thickness to examine the effect of changing the size of the Bragg peak and the number of required energy layers. The parameters with which 95% of the tumor trajectory data fulfill our defined criteria were accepted. Next, correlation coefficients were calculated between the maximum dose error and the tumor motion characteristics that were extracted from the tumor trajectory data. Results: With the assumed CTV, the largest percentage of the data fulfilled the criteria when the gate width was +/- 2 mm. Larger spot spacing was preferred because it increased the number of paintings. With a prescribed dose of 2 Gy, it was difficult to fulfill the criteria for the target with a very small effective depth (the sum of an assumed energy absorber's thickness and the target depth in the phantom) because of the sharpness of the Bragg peak. However, even shallow targets could be successfully irradiated by employing an adequate number of paintings and by placing an energy absorber of sufficient thickness to make the effective target depth more than 12 cm. The authors also observed that motion in the beam direction was the main cause of dose distortion, followed by motion in the lateral plane perpendicular to the scan direction. Conclusions: The results suggested that by properly adjusting irradiation control parameters, gated proton spot-scanning beam therapy can be robust to target motion. This is an important first step toward establishing treatment plans in real patient geometry. (C) 2013 American Association of Physicists in Medicine.
• Stereotactic body radiotherapy using gated radiotherapy with real-time tumor-tracking for stage I non-small cell lung cancer

  Tetsuya Inoue, Norio Katoh, Rikiya Onimaru, Shinichi Shimizu, Kazuhiko Tsuchiya, Ryusuke Suzuki, Jun Sakakibara-Konishi, Naofumi Shinagawa, Satoshi Oizumi, Hiroki Shirato

  Radiation Oncology 8 1 69  2013年03月21日 [査読有り][通常論文]
   

  Background: To clarify the clinical outcomes of two dose schedule of stereotactic body radiotherapy (SBRT) for stage I non-small cell lung cancer (NSCLC) using a real-time tumor-tracking radiation therapy (RTRT) system in single institution.Methods: Using a superposition algorithm, we administered 48 Gy in 4 fractions at the isocenter in 2005-2006 and 40 Gy in 4 fractions to the 95% volume of PTV in 2007-2010 with a treatment period of 4 to 7 days. Target volume margins were fixed irrespective of the tumor amplitude.Results: In total, 109 patients (79 T1N0M0 and 30 T2N0M0). With a median follow-up period of 25 months (range, 4 to 72 months), the 5-year local control rate (LC) was 78% and the 5-year overall survival rate (OS) was 64%. Grade 2, 3, 4, and 5 radiation pneumonitis (RP) was experienced by 15 (13.8%), 3 (2.8%), 0, and 0 patients, respectively. The mean lung dose (MLD) and the volume of lung receiving 20 Gy (V20) were significantly higher in patients with RP Grade 2/3 than in those with RP Grade 0/1 (MLD p = 0.002, V20 p = 0.003). There was no correlation between larger maximum amplitude of marker movement and larger PTV (r = 0.137), MLD (r = 0.046), or V20 (r = 0.158).Conclusions: SBRT using the RTRT system achieved LC and OS comparable to other SBRT studies with very low incidence of RP, which was consistent with the small MLD and V20 irrespective of tumor amplitude. For stage I NSCLC, SBRT using RTRT was suggested to be reliable and effective, especially for patients with large amplitude of tumor movement. © 2013 Inoue et al.; licensee BioMed Central Ltd.
• What is the appropriate size criterion for proton radiotherapy for hepatocellular carcinoma? A dosimetric comparison of spot-scanning proton therapy versus intensity-modulated radiation therapy

  Chie Toramatsu, Norio Katoh, Shinichi Shimizu, Hideaki Nihongi, Taeko Matsuura, Seishin Takao, Naoki Miyamoto, Ryusuke Suzuki, Kenneth Sutherland, Rumiko Kinoshita, Rikiya Onimaru, Masayori Ishikawa, Kikuo Umegaki, Hiroki Shirato

  RADIATION ONCOLOGY 8 48  2013年03月 [査読有り][通常論文]
   

  Background: We performed a dosimetric comparison of spot-scanning proton therapy (SSPT) and intensity-modulated radiation therapy (IMRT) for hepatocellular carcinoma (HCC) to investigate the impact of tumor size on the risk of radiation induced liver disease (RILD). Methods: A number of alternative plans were generated for 10 patients with HCC. The gross tumor volumes (GTV) varied from 20.1 to 2194.5 cm(3). Assuming all GTVs were spherical, the nominal diameter was calculated and ranged from 3.4 to 16.1 cm. The prescription dose was 60 Gy for IMRT or 60 cobalt Gy-equivalents for SSPT with 95% planning target volume (PTV) coverage. Using IMRT and SSPT techniques, extensive comparative planning was conducted. All plans were evaluated by the risk of RILD estimated using the Lyman-normal-tissue complication probability model. Results: For IMRT the risk of RILD increased drastically between 6.3-7.8 cm nominal diameter of GTV. When the nominal diameter of GTV was more than 6.3 cm, the average risk of RILD was 94.5% for IMRT and 6.2% for SSPT. Conclusions: Regarding the risk of RILD, HCC can be more safely treated with SSPT, especially if its nominal diameter is more than 6.3 cm.
• フィルム線量解析における読取装置不安定性に起因する誤差の低減方法

  石川 正純, 小島 秀樹, 橘 英伸, 鈴木 隆介, 峯村 俊行, 遠山 尚紀, 成田 雄一郎, 西尾 禎治, 石倉 聡

  日本医学放射線学会学術集会抄録集 72回 S407 - S407 (公社)日本医学放射線学会 2013年02月
• [F-18]fluoromisonidazole and a New PET System With Semiconductor Detectors and a Depth of Interaction System for Intensity Modulated Radiation Therapy for Nasopharyngeal Cancer

  Koichi Yasuda, Rikiya Onimaru, Shozo Okamoto, Tohru Shiga, Norio Katoh, Kazuhiko Tsuchiya, Ryusuke Suzuki, Wataru Takeuchi, Yuji Kuge, Nagara Tamaki, Hiroki Shirato

  INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS 85 1 142 - 147 2013年01月 [査読有り][通常論文]
   

  Purpose: The impact of a new type of positron emission tomography (New PET) with semiconductor detectors using F-18-labeled fluoromisonidazole (FMISO)-guided intensity modulated radiation therapy (IMRT) was compared with a state-of-the-art PET/computed tomography (PET/CT) system in nasopharyngeal cancer (NPC) patients. Methods and Materials: Twenty-four patients with non-NPC malignant tumors (control group) and 16 patients with NPC were subjected to FMISO-PET. The threshold of the tumor-to-muscle (T/M) ratio in each PET scan was calculated. The hypoxic volume within the gross tumor volume (GTVh) was determined using each PET ((NewPET)GTVh and (PET/CT)GTVh, respectively). Dose escalation IMRT plans prescribing 84 Gy to each GTVh were carried out. Results: The threshold of the T/M ratio was 1.35 for New PET and 1.23 for PET/CT. The mean volume of NewPETGTVh was significantly smaller than that of PET/CTGTVh (1.5 +/- 1.6 cc vs 4.7 +/- 4.6 cc, respectively; P = .0020). The dose escalation IMRT plans using New PET were superior in dose distribution to those using PET/CT. Dose escalation was possible in all 10 New PET-guided plans but not in 1 PET/CT-guided plan, because the threshold dose to the brainstem was exceeded. Conclusions: New PET was found to be useful for accurate dose escalation in FMISO-guided IMRT for patients with NPC. (c) 2013 Elsevier Inc.
• [18F]fluoromisonidazole and a new PET system with semiconductor detectors and a depth of interaction system for intensity modulated radiation therapy for nasopharyngeal cancer

  Yasuda K, Onimaru R, Okamoto S, Shiga T, Katoh N, Tsuchiya K, Suzuki R, Takeuchi W, Kuge Y, Tamaki N, Shirato H

  Int J Radiat Oncol Biol Phys 85 1 142 - 7 2013年 [査読有り][通常論文]
  
• Can 4DCT Imaging Predict Lung Motion During Stereotactic Body Radiation Therapy?

  Harada K, Katoh N, Suzuki R, Inoue T, Omimaru R, Shimizu S, Miyamoto N, Ishikawa M, Shirato H

  International Journal of Radiation Oncology Biology Physics 87 2 S67  2013年 [査読有り][通常論文]
  
• マルチベンダに対応した放射線治療計画管理システムの開発

  辻 真太朗, 谷川原 綾子, 鈴木 隆介, 宮崎 智夫, 藤田 勝久, 石川 正純, 白土 博樹

  医療情報学連合大会論文集 32回 1444 - 1445 (一社)日本医療情報学会 2012年11月
• 一方向X線透視による低被曝・省スペース型動体追跡装置の開発

  宮本直樹, 石川正純, SUTHERLAND Kenneth, 鈴木隆介, 松浦妙子, 高尾聖心, 寅松千枝, 二本木英明, 清水伸一, 梅垣菊男, 白土博樹

  医学物理 Supplement 32 3 281 - 282 2012年09月13日 [査読無し][通常論文]
  
• 体内複数マーカを用いた高精度ゲーティング照射法の基礎検討

  大友可奈子, 宮本直樹, SUTHERLAND Kenneth, 鈴木隆介, 松浦妙子, 鬼丸力也, 清水伸一, 梅垣菊男, 白土博樹, 石川正純

  医学物理 Supplement 32 3 155 - 156 2012年09月13日 [査読無し][通常論文]
  
• Biological effect of dose distortion by fiducial markers in spot-scanning proton therapy with a limited number of fields: A simulation study

  Taeko Matsuura, Kenichiro Maeda, Kenneth Sutherland, Taisuke Takayanagi, Shinichi Shimizu, Seishin Takao, Naoki Miyamoto, Hideaki Nihongi, Chie Toramatsu, Yoshihiko Nagamine, Rintaro Fujimoto, Ryusuke Suzuki, Masayori Ishikawa, Kikuo Umegaki, Hiroki Shirato

  MEDICAL PHYSICS 39 9 5584 - 5591 2012年09月 [査読有り][通常論文]
   

  Purpose: In accurate proton spot-scanning therapy, continuous target tracking by fluoroscopic x ray during irradiation is beneficial not only for respiratory moving tumors of lung and liver but also for relatively stationary tumors of prostate. Implanted gold markers have been used with great effect for positioning the target volume by a fluoroscopy, especially for the cases of liver and prostate with the targets surrounded by water-equivalent tissues. However, recent studies have revealed that gold markers can cause a significant underdose in proton therapy. This paper focuses on prostate cancer and explores the possibility that multiple-field irradiation improves the underdose effect by markers on tumor-control probability (TCP). Methods: A Monte Carlo simulation was performed to evaluate the dose distortion effect. A spherical gold marker was placed at several characteristic points in a water phantom. The markers were with two different diameters of 2 and 1.5 mm, both visible on fluoroscopy. Three beam arrangements of single-field uniform dose (SFUD) were examined: one lateral field, two opposite lateral fields, and three fields (two opposite lateral fields + anterior field). The relative biological effectiveness (RBE) was set to 1.1 and a dose of 74 Gy (RBE) was delivered to the target of a typical prostate size in 37 fractions. The ratios of TCP to that without the marker (TCPr) were compared with the parameters of the marker sizes, number of fields, and marker positions. To take into account the dependence of biological parameters in TCP model, alpha/beta values of 1.5, 3, and 10 Gy (RBE) were considered. Results: It was found that the marker of 1.5 mm diameter does not affect the TCPs with all alpha/beta values when two or more fields are used. On the other hand, if the marker diameter is 2 mm, more than two irradiation fields are required to suppress the decrease in TCP from TCPr by less than 3%. This is especially true when multiple (two or three) markers are used for alignment of a patient. Conclusions: It is recommended that 1.5-mm markers be used to avoid the reduction of TCP as well as to spare the surrounding critical organs, as long as the markers are visible on x-ray fluoroscopy. When 2-mm markers are implanted, more than two fields should be used and the markers should not be placed close to the distal edge of any of the beams. (c) 2012 American Association of Physicists in Medicine. [http://dx.doi.org/10.1118/1.4745558]
• 胃悪性リンパ腫に対する迎撃照射とマーカー移動の解析

  加藤徳雄, 鈴木隆介, 井上哲也, 安田耕一, 鬼丸力也, 清水伸一, 木村理奈, 石川正純, 白土博樹

  日本医学放射線学会総会抄録集 71st S316 - S316 (公社)日本医学放射線学会 2012年02月29日 [査読無し][通常論文]
  
• Improvement of tracking accuracy and stability by recursive image processing in real-time tumor-tracking radiotherapy system

  Naoki Miyamoto, Kenneth Sutherland, Ryusuke Suzuki, Taeko Matsuura, Chie Toramatsu, Seishin Takao, Hideaki Nihongi, Rumiko Kinoshita, Shinichi Shimizu, Rikiya Onimaru, Kikuo Umegaki, Hiroki Shirato, Masayori Ishikawa

  MEDICAL IMAGING 2012: IMAGE-GUIDED PROCEDURES, ROBOTIC INTERVENTIONS, AND MODELING 8316 2012年 [査読有り][通常論文]
   

  In the real-time tumor-tracking radiotherapy (RTRT) system, the fiducial markers are inserted in or near the target tumor in order monitor the respiratory-induced motion of tumors. During radiation treatment, the markers are detected by continuous fluoroscopy operated at 30 frames/sec. The marker position is determined by means of a template pattern matching technique which is based on the normalized cross correlation. With high tube voltage, large current and long exposure, the fiducial marker will be recognized accurately, however, the radiation dose due to X-ray fluoroscopy increases. On the other hand, by decreasing the fluoroscopy parameter settings, the fiducial marker could be lost because the effect of statistical noise is increased. In the respiratory-gated radiotherapy, the error of the image guidance will induce the reduction of the irradiation efficiency and accuracy. In order to track the marker stably and accurately in low dose fluoroscopy, we propose the application of a recursive filter. The effectiveness of the image processing is investigated by tracking the static marker and the dynamic marker. The results suggest that the stability and the accuracy of the marker tracking can be improved by applying the recursive image filter in low dose imaging.
• Real-time Tumor-tracking Radiation Therapy for Lymphoma of the Stomach

  Katoh N, Suzuki R, Shimizu S, Inoue T, Yasuda K, Onimaru R, Kimura R, Kato M, Ishikawa M, Shirato H

  International Journal of Radiation Oncology Biology Physics 84 3 S722  2012年 [査読有り][通常論文]
  
• ACCURATE ANALYSIS OF THE CHANGE IN VOLUME, LOCATION, AND SHAPE OF METASTATIC CERVICAL LYMPH NODES DURING RADIOTHERAPY

  Seishin Takao, Shigeru Tadano, Hiroshi Taguchi, Koichi Yasuda, Rikiya Onimaru, Masayori Ishikawa, Gerard Bengua, Ryusuke Suzuki, Hiroki Shirato

  INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS 81 3 871 - 879 2011年11月 [査読有り][通常論文]
   

  Purpose: To establish a method for the accurate acquisition and analysis of the variations in tumor volume, location, and three-dimensional (3D) shape of tumors during radiotherapy in the era of image-guided radiotherapy. Methods and Materials: Finite element models of lymph nodes were developed based on computed tomography (CT) images taken before the start of treatment and every week during the treatment period. A surface geometry map with a volumetric scale was adopted and used for the analysis. Six metastatic cervical lymph nodes, 3.5 to 55.1 cm before treatment, in 6 patients with head and neck carcinomas were analyzed in this study. Three fiducial markers implanted in mouthpieces were used for the fusion of CT images. Changes in the location of the lymph nodes were measured on the basis of these fiducial markers. Results: The surface geometry maps showed convex regions in red and concave regions in blue to ensure that the characteristics of the 3D tumor geometries are simply understood visually. After the irradiation of 66 to 70 Gy in 2 Gy daily doses, the patterns of the colors had not changed significantly, and the maps before and during treatment were strongly correlated (average correlation coefficient was 0.808), suggesting that the tumors shrank uniformly, maintaining the original characteristics of the shapes in all 6 patients. The movement of the gravitational center of the lymph nodes during the treatment period was everywhere less than +/-5 mm except in 1 patient, in whom the change reached nearly 10 mm. Conclusions: The surface geometry map was useful for an accurate evaluation of the changes in volume and 3D shapes of metastatic lymph nodes. The fusion of the initial and follow-up CT images based on fiducial markers enabled an analysis of changes in the location of the targets. Metastatic cervical lymph nodes in patients were suggested to decrease in size without significant changes in the 3D shape during radiotherapy. The movements of the gravitational center of the lymph nodes were almost all less than +/-5 mm. (C) 2011 Elsevier Inc.
• USE OF IMPLANTED MARKERS AND INTERPORTAL ADJUSTMENT WITH REAL-TIME TRACKING RADIOTHERAPY SYSTEM TO REDUCE INTRAFRACTION PROSTATE MOTION

  Shinichi Shimizu, Yasuhiro Osaka, Nobuo Shinohara, Ataru Sazawa, Kentaro Nishioka, Ryusuke Suzuki, Rikiya Onimaru, Hiroki Shirato

  INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS 81 4 E393 - E399 2011年11月 [査読有り][通常論文]
   

  Purpose: Interportal adjustment was applied to patients with prostate cancer using three fiducial markers and two sets of fluoroscopy in a real-time tumor-tracking radiotherapy (RTRT) system. The incidence of table position adjustment required to keep intrafractional uncertainty within 2.0 mm was investigated in this study. Methods and Materials: The coordinates of the center of gravity of the three fiducial markers were measured at the start of every portal irradiation in intensity-modulated radiotherapy (IMRT) with seven ports. The table position was adjusted to the planned position if the discrepancy was larger than 2.0 mm in the anterior-posterior (AP), cranial-caudal (CC), or left-right (LR) directions. In total, we analyzed 4,541 observations in 20 patients who received 70 Gy in 30 fractions (7.6 times a day on average). Results: The incidence of table position adjustment at 10 minutes from the initial setup of each treatment was 14.2%, 12.3%, and 5.0% of the observations in the AP, CC, and LR directions, respectively. The accumulated incidence of the table position adjustment was significantly higher at 10 minutes than at 2 minutes for AP (p = 0.0033) and CC (p = 0.0110) but not LR (p = 0.4296). An adjustment greater than 5 mm was required at least once in the treatment period in 11 (55%) patients. Conclusions: Interportal adjustment of table position was required in more than 10% of portal irradiations during the 10-minute period after initial setup to maintain treatment accuracy within 2.0 mm. (C) 2011 Elsevier Inc.
• Optimization of fluoroscopy parameters using pattern matching prediction in the real-time tumor-tracking radiotherapy system

  Naoki Miyamoto, Masayori Ishikawa, Gerard Bengua, Kenneth Sutherland, Ryusuke Suzuki, Suguru Kimura, Shinichi Shimizu, Rikiya Onimaru, Hiroki Shirato

  PHYSICS IN MEDICINE AND BIOLOGY 56 15 4803 - 4813 2011年08月 [査読有り][通常論文]
   

  In the real-time tumor-tracking radiotherapy system, fluoroscopy is used to determine the real-time position of internal fiducial markers. The pattern recognition score (PRS) ranging from 0 to 100 is computed by a template pattern matching technique in order to determine the marker position on the fluoroscopic image. The PRS depends on the quality of the fluoroscopic image. However, the fluoroscopy parameters such as tube voltage, current and exposure duration are selected manually and empirically in the clinical situation. This may result in an unnecessary imaging dose from the fluoroscopy or loss of the marker because of too much or insufficient x-ray exposure. In this study, a novel optimization method is proposed in order to minimize the fluoroscopic dose while keeping the image quality usable for marker tracking. The PRS can be predicted in a region where the marker appears to move in the fluoroscopic image by the proposed method. The predicted PRS can be utilized to judge whether the marker can be tracked with accuracy. In this paper, experiments were performed to show the feasibility of the PRS prediction method under various conditions. The predicted PRS showed good agreement with the measured PRS. The root mean square error between the predicted PRS and the measured PRS was within 1.44. An experiment using a motion controller and an anthropomorphic chest phantom was also performed in order to imitate a clinical fluoroscopy situation. The result shows that the proposed prediction method is expected to be applicable in a real clinical situation.
• Long-term Outcomes of Fractionated Stereotactic Radiotherapy for Intracranial Skull Base Benign Meningiomas in Single Institution

  Shunsuke Onodera, Hidefumi Aoyama, Norio Katoh, Hiroshi Taguchi, Kouichi Yasuda, Daisuke Yoshida, Ken Surtherland, Ryusuke Suzuki, Masayori Ishikawa, Bengua Gerard, Shunsuke Terasaka, Hiroki Shirato

  JAPANESE JOURNAL OF CLINICAL ONCOLOGY 41 4 462 - 468 2011年04月 [査読有り][通常論文]
   

  Objective: To investigate the outcome of linac-based fractionated stereotactic radiotherapy over the last 10 years for intracranial skull base benign meningiomas in patients who were inoperable, who had residual tumors with some components of high mitotic index after surgery and who experienced relapse of the tumor. Methods: Twenty-seven patients with intracranial skull base benign meningiomas treated with fractionated stereotactic radiotherapy were retrospectively reviewed. Twenty-seven cases were diagnosed as benign meningiomas on pathological (17 cases) or radiological (10 cases) examination. The median follow-up time was 90 months after initial treatment and 63 months after fractionated stereotactic radiotherapy. The median biological equivalent dose calculated using an alpha/beta ratio of 2.0 Gy was 82.0 Gy (range, 60-106 Gy). Results: The 5-year overall survival was 95.7 (95% confidence interval: 87.3-100)% after initial treatment and 96.2 (88.8-100)% after fractionated stereotactic radiotherapy. The 5-year overall survival and local control rate of patients who received fractionated stereotactic radiotherapy alone were both 100%. The 5-year progression-free survival and local control rate after fractionated stereotactic radiotherapy were all 100% with a tumor volume of <9.1 cc and 68.2 (37.2-99.2) and 75.8 (45.2-100)% for the tumors 9.1 cc, respectively. The difference was significant in progression-free survival (P=0.022) and local control rate (P=0.044). The local control rate was significantly worse in patients who received fractionated stereotactic radiotherapy for relapsed tumors (P=0.01). No late radiation damage was observed in the follow-up period. Conclusions: The long-term outcome suggests that fractionated stereotactic radiotherapy is a safe and effective treatment for intracranial skull base benign meningioma, especially for those who have tumors <9.1 cc or would receive fractionated stereotactic radiotherapy with or without surgery as the initial treatment.
• A feasibility study of a molecular-based patient setup verification method using a parallel-plane PET system

  Satoshi Yamaguchi, Masayori Ishikawa, Gerard Bengua, Kenneth Sutherland, Teiji Nishio, Satoshi Tanabe, Naoki Miyamoto, Ryusuke Suzuki, Hiroki Shirato

  PHYSICS IN MEDICINE AND BIOLOGY 56 4 965 - 977 2011年02月 [査読有り][通常論文]
   

  A feasibility study of a novel PET-based molecular image guided radiation therapy (m-IGRT) system was conducted by comparing PET-based digitally reconstructed planar image (PDRI) registration with radiographic registration. We selected a pair of opposing parallel-plane PET systems for the practical implementation of this system. Planar images along the in-plane and cross-plane directions were reconstructed from the parallel-plane PET data. The in-plane and cross-plane FWHM of the profile of 2 mm diameter sources was approximately 1.8 and 8.1 mm, respectively. Therefore, only the reconstructed in-plane image from the parallel-plane PET data was used in the PDRI registration. In the image registration, five different sizes of (18)F cylindrical sources (diameter: 8, 12, 16, 24, 32 mm) were used to determine setup errors. The data acquisition times were 1, 3 and 5 min. Image registration was performed by five observers to determine the setup errors from PDRI registration and radiographic registration. The majority of the mean registration errors obtained from the PDRI registration were not significantly different from those obtained from the radiographic registration. Acquisition time did not appear to result in significant differences in the mean registration error. The mean registration error for the PDRI registration was found to be 0.93 +/- 0.33 mm. This is not statistically different from the radiographic registration which had a mean registration error of 0.92 +/- 0.27 mm. Our results suggest that m-IGRT image registration using PET-based reconstructed planar images along the in-plane direction is feasible for clinical use if PDRI registration is performed at two orthogonal gantry angles.
• Use of implanted markers and interportal adjustment with real-time tracking radiotherapy system to reduce intrafraction prostate motion.

  Shimizu S, Osaka Y, Shinohara N, Sazawa A, Nishioka K, Suzuki R, Onimaru R, Shirato H

  Int J Radiat Oncol Biol Phys 81 4 e393 - 9 2011年 [査読有り][通常論文]
  
• Optimization of fluoroscopy parameters using pattern matching prediction in the real-time tumor-tracking radiotherapy system.

  Miyamoto N, Ishikawa M, Bengua G, Sutherland K, Suzuki R, Kimura S, Shimizu S, Onimaru R, Shirato H

  Phys Med Biol 56 15 4803 - 13 2011年 [査読有り][通常論文]
   

  In the real-time tumor-tracking radiotherapy system, fluoroscopy is used to determine the real-time position of internal fiducial markers. The pattern recognition score (PRS) ranging from 0 to 100 is computed by a template pattern matching technique in order to determine the marker position on the fluoroscopic image. The PRS depends on the quality of the fluoroscopic image. However, the fluoroscopy parameters such as tube voltage, current and exposure duration are selected manually and empirically in the clinical situation. This may result in an unnecessary imaging dose from the fluoroscopy or loss of the marker because of too much or insufficient x-ray exposure. In this study, a novel optimization method is proposed in order to minimize the fluoroscopic dose while keeping the image quality usable for marker tracking. The PRS can be predicted in a region where the marker appears to move in the fluoroscopic image by the proposed method. The predicted PRS can be utilized to judge whether the marker can be tracked with accuracy. In this paper, experiments were performed to show the feasibility of the PRS prediction method under various conditions. The predicted PRS showed good agreement with the measured PRS. The root mean square error between the predicted PRS and the measured PRS was within 1.44. An experiment using a motion controller and an anthropomorphic chest phantom was also performed in order to imitate a clinical fluoroscopy situation. The result shows that the proposed prediction method is expected to be applicable in a real clinical situation.
• Accurate analysis of the change in volume, location, and shape of metastatic cervical lymph nodes during radiotherapy.

  Takao S, Tadano S, Taguchi H, Yasuda K, Onimaru R, Ishikawa M, Bengua G, Suzuki R, Shirato H

  Int J Radiat Oncol Biol Phys 81 3 871 - 9 2011年 [査読有り][通常論文]
  
• 生物学的効果を考慮した治療計画—Dose Volume Histogram解析による考察—

  関原和正, 石川正純, SUTHERLAND Kenneth, BENGUA Gerard, 宮本直樹, 鈴木隆介, 清水伸一, 白土博樹

  Jpn J Radiol 28 Supplement 1 15 - 15 (公社)日本医学放射線学会 2010年07月25日 [査読無し][通常論文]
  
• H&N癌のための18F‐フルオロミソニダゾールPETの影響とIMRTへの適用

  安田耕一, 長谷川雅一, 鬼丸力也, 木下留美子, 加藤徳雄, 田口大志, 清水伸一, 井上哲也, 小野寺俊輔, 溝口史樹, 青山英史, 白土博樹, 志賀哲, 岡本祥三, 玉木長良, 石川正純, SUTHERLAND Kenneth, BENGUA Gerard, 宮本直樹, 鈴木隆介

  Jpn J Radiol 28 Supplement 1 14 - 14 (公社)日本医学放射線学会 2010年07月25日 [査読無し][通常論文]
  
• 動体追跡装置におけるコントラスト‐ノイズ比の測定方法の検討

  木村傑, 宮本直樹, 石川正純, SUTHERLAND Kenneth, BENGUA Gerard, 鈴木隆介, 清水伸一, 青山英史, 鬼丸力也, 白土博樹

  医学物理 Supplement 29 3 148-149  2009年09月 [査読無し][通常論文]
  
• 動体追跡放射線治療におけるX線透視条件の最適化

  宮本直樹, SUTHERLAND Kenneth, 石川正純, 鈴木隆介, BENGUA Gerard, 木村傑, 清水伸一, 青山英史, 鬼丸力也, 白土博樹

  医学物理 Supplement 29 3 150-151  2009年09月 [査読無し][通常論文]
  
• 動体追跡装置を用いた肺定位照射時の投与線量解析—動体追跡データに基づくDVH解析—

  石川正純, サザランド ケネス, ベングア ジェラード, 鈴木隆介, 宮本直樹, 加藤徳雄, 清水伸一, 鬼丸力也, 青山英史, 白土博樹

  日本放射線腫よう学会誌 21 Supplement 1 158  2009年08月19日 [査読無し][通常論文]
  
• 対向型PET装置を用いた分子イメージング動体追跡装置の開発〜¹⁸F点線源を用いた追跡精度の検証〜

  棚邊哲史, 石川正純, 山口哲, 武島嗣英, 鈴木隆介, 宮本直樹, 加藤徳雄, 清水伸一, 鬼丸力也, 白土博樹

  医学物理 Supplement 29 2 101-102  2009年04月 [査読無し][通常論文]
  
• 体内臓器同期照射を目的とした次世代動体追跡装置の開発〜透視画像の歪みと位置計算誤差〜

  宮本直樹, SUTHERLAND Kenneth, 石川正純, 鈴木隆介, BENGUA Gerard, 木村傑, 清水伸一, 青山英史, 鬼丸力也, 白土博樹

  医学物理 Supplement 29 2 192-193  2009年04月 [査読無し][通常論文]
  
• 体内臓器同期照射を目的とした次世代動体追跡装置の開発〜デジタル画像機器としての定量的評価〜

  木村傑, 石川正純, SUTHERLAND Kenneth, 宮本直樹, BENGUA Gerard, 鈴木隆介, 清水伸一, 青山英史, 鬼丸力也, 白土博樹

  医学物理 Supplement 29 2 196-197  2009年04月 [査読無し][通常論文]
  
• Can the Real-time Tumor-tracking Radiotherapy Give the Planned Dose to the Tumor? DVH Analysis Based on Measured Real-time Tracking Data

  Ishikawa M, Sutherland KL, Bengua G, Suzuki R, Miyamoto N, Katoh N, Shimizu S, Onimaru R, Aoyama H, Shirato

  International Journal of Radiation Oncology Biology Physics 75 3 S590 - S591 2009年 [査読有り][通常論文]
  
• Continuum level density of a coupled-channel system in the complex scaling method

  Ryusuke Suzuki, Andras T. Kruppa, Bertrand G. Giraud, Kiyoshi Kato

  PROGRESS OF THEORETICAL PHYSICS 119 6 949 - 963 2008年06月 [査読有り][通常論文]
   

  We study the continuum level density (CLD) in the formalism of the complex scaling method (CSM) for coupled-channel systems. We apply the formalism to the He-4 = [H-3 + p] + [He-3 + n] coupled-channel cluster model where there are resonances at low energy. Numerical calculations of the CLD in the CSM with a finite number of L-2 basis functions are consistent with the exact result calculated from the S-matrix by solving coupled-channel equations. We also study channel densities. In this framework, the extended completeness relation (ECR) plays an important role.
• Scattering amplitude without an explicit enforcement of boundary conditions

  A. T. Kruppa, R. Suzuki, K. Kato

  Physical Review C - Nuclear Physics 75 4 2007年04月11日 [査読有り][通常論文]
   

  It has been known for some time that for short range potentials scattering observables can be calculated using complex coordinates. We will show that the standard uniform complex scaling can be applied to calculate the scattering amplitude even in the presence of a long range interaction. The main advantage of the application of the complex scaling to the scattering problem is that the direct imposition of the complicated scattering boundary condition can be avoided. As a result, the scattering problem can be solved using only square integrable functions. The method will be applied not only for potential scattering but for the coupled-channel reaction model. As an application we calculate the phase shifts of the charge exchange reaction H3(p,n)He3. © 2007 The American Physical Society.
• Scattering amplitude without an explicit enforcement of boundary conditions

  A. T. Kruppa, R. Suzuki, K. Kato

  PHYSICAL REVIEW C 75 4 044602  2007年04月 [査読有り][通常論文]
   

  It has been known for some time that for short range potentials scattering observables can be calculated using complex coordinates. We will show that the standard uniform complex scaling can be applied to calculate the scattering amplitude even in the presence of a long range interaction. The main advantage of the application of the complex scaling to the scattering problem is that the direct imposition of the complicated scattering boundary condition can be avoided. As a result, the scattering problem can be solved using only square integrable functions. The method will be applied not only for potential scattering but for the coupled-channel reaction model. As an application we calculate the phase shifts of the charge exchange reaction H-3(p,n)He-3.
• Level density in the complex scaling method

  R Suzuki, T Myo, K Kato

  PROGRESS OF THEORETICAL PHYSICS 113 6 1273 - 1286 2005年06月 [査読有り][通常論文]
   

  It is shown that the continuum level density (CLD) at unbound energies can be calculated with the complex scaling method (CSM), in which the energy spectra of bound states, resonances and continuum states are obtained in terms of L-2 basis functions. In this method, the extended completeness relation is applied to the calculation of the Green functions, and the continuum-state part is approximately expressed in terms of discretized complex scaled continuum solutions. The obtained result is compared with the CLD calculated exactly from the scattering phase shift. The discretization in the CSM is shown to give a very good description of continuum states. We discuss how the scattering phase shifts can inversely be calculated from the discretized CLD using a basis function technique in the CSM.
• Analysis of Be-11 in the Be-10+n model

  R Suzuki, T Myo, K Kato, K Ikeda

  PROGRESS OF THEORETICAL PHYSICS SUPPLEMENT 146 626 - 627 2002年 [査読有り][通常論文]
  
• Low-energy spectrum of one-neutron halo nucleus Be-11

  R Suzuki, T Myo, K Kato, K Ikeda

  ACTA PHYSICA HUNGARICA NEW SERIES-HEAVY ION PHYSICS 13 1-3 169 - 173 2001年 [査読有り][通常論文]
   

  We investigate the low-energy spectrum of the one-neutron halo nucleus Be-11 using the complex scaled coupled channel method for a Be-10 + n model, paying attention to the effects of the deformation of the Be-10-core and the Pauli principle between the core and a valence neutron. For positive parity states of Be-11, our calculation well reproduces the experimental results, but for negative parity states, not so well. With reducing the coupling between the core deformation and a valence neutron, the negative parity levels of the Be-11 nucleus are much improved.

その他活動・業績

• 強度変調放射線治療(IMRT)を行った下咽頭癌における再発症例の検討

  大塚愛美, 安田耕一, 湊川英樹, 出倉康裕, 青山英史, 清水伸一, 鈴木隆介, 宮本直樹, 清水伸一, 鈴木崇祥, 対馬那由多, 加納里志, 田口純, 清水康, 本間明宏, 清水伸一 Japanese Journal of Radiology 40 (Supplement) 2022年
• Automatic Bladder Delineation on MR Images Using a Convolution Neural Network for Online Image-Guided Radiotherapy

  K. Nishioka, Y. Nomura, T. Hashimoto, R. Kinoshita, N. Katoh, H. Taguchi, K. Yasuda, T. Mori, Y. Uchinami, M. Otsuka, T. Matsuura, S. Takao, R. Suzuki, S. Tanaka, T. Yoshimura, H. Aoyama, S. Shimizu International Journal of Radiation Oncology*Biology*Physics 108 (3) e288 -e289 2020年11月 [査読有り]
  
• 前立腺癌治療の新たな展開:ハイリスク前立腺癌に対する拡大手術、粒子線治療、ネオアジュバント治療 ハイリスク前立腺がんに対する強度変調放射線治療・陽子線治療 現状と可能性

  清水 伸一, 橋本 孝之, 西岡 健太郎, 安部 崇重, 大澤 崇宏, 松本 隆児, 松浦 妙子, 宮本 直樹, 高尾 聖心, 鈴木 隆介, 梅垣 菊男, 篠原 信雄, 白土 博樹 日本癌治療学会学術集会抄録集 56回 SY5 -2 2018年10月 [査読無し][通常論文]
  
• 全脳全脊髄照射におけるスポットスキャニング陽子線治療とIMRTによる誘発二次発がん率の比較

  鈴木俊介, 田村昌也, 鈴木隆介, 高尾聖心, 橋本孝之, 清水伸一, 白土博樹 日本放射線腫瘍学会高精度放射線外部照射部会学術大会プログラム・抄録集 31st (CD-ROM) 2018年
• 頭蓋底腫瘍術後に強度変調放射線治療を行った2例

  森崇, 宮本直樹, 鈴木隆介, 鬼丸力也, 白土博樹 Japanese Journal of Radiology 35 (Supplement) 4 2017年02月25日 [査読無し][通常論文]
  
• Radiation Dose to Internal Mammary Lymph Node in Standard Tangential Breast Irradiation

  R. Kinoshita, S. Shimizu, Y. Nishikawa, K. Nishioka, T. Hashimoto, R. Suzuki, H. Shirato INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS 96 (2) E17 -E18 2016年10月 [査読無し][通常論文]
  
• 食道IMRTにおけるintra-fractional organ motionの影響

  田村 弘詞, 宮本 直樹, 鈴木 隆介, 堀田 賢治, 藤田 勝久, 井上 哲也 日本放射線技術学会雑誌 72 (9) 873 -874 2016年09月 [査読無し][通常論文]
  
• An Evaluation Method of Lifetime Attributable Risk for Comparing Between Proton Beam Therapy and Intensity Modulated X-Ray Therapy for Pediatric Cancer Patients by Averaging Four Dose-Response Models for Carcinoma Induction

  M. Tamura, Y. Ito, H. Sakurai, M. Mizumoto, S. Kamizawa, S. Murayama, H. Yamashita, S. Takao, R. Suzuki, H. Shirato MEDICAL PHYSICS 43 (6) 3508 -3508 2016年06月 [査読無し][通常論文]
  
• 椎体IMRTとその精度に関する研究

  安田耕一, 清水伸一, 橋本孝之, SUTHERLAND Ken, 白土博樹, 土屋和彦, 加藤徳雄, 鬼丸力也, 木下留美子, 井上哲也, 西岡健太郎, 西川由記子, 森崇, 原田慶一, 原田八重, 鈴木隆介, 寅松千枝, 松浦妙子, 高尾聖心, 宮本直樹, 伊藤陽一 Japanese Journal of Radiology 34 (Supplement) 5 -5 2016年02月25日 [査読無し][通常論文]
  
• Development of Digitization Software GSYS for NRDF/EXFOR compilation

  R. Suzuki, A. Makinaga, M. Aikawa Proceedings of the 2014 Symposium on Nuclear Data 2016年 [査読有り][通常論文]
  
• Target Residual Motion During Beam Delivery in Gated Irradiation Using Real Time Tumor Tracking Radiation Therapy System: Analysis of Simultaneous Motion of Multiple Internal Fiducial Markers

  N. Miyamoto, M. Ishikawa, R. Suzuki, A. Makinaga, T. Matsuura, S. Takao, Y. Matsuzaki, T. Inoue, N. Katoh, S. Shimizu, R. Onimaru, H. Shirato INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS 93 (3) E554 -E554 2015年11月 [査読無し][通常論文]
  
• NTCP Modeling Analysis of Acute Hematologic Toxicity in Whole-Pelvic Radiation Therapy for Gynecologic Malignancies: A Dosimetric Comparison of IMRT and Spot-Scanning Proton Therapy

  T. Yoshimura, R. Kinoshita, S. Onodera, C. Toramatsu, R. Suzuki, Y. M. Ito, S. Takao, T. Matsuura, Y. Matsuzaki, S. Shimizu, K. Umegaki, H. Shirato INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS 93 (3) E254 -E254 2015年11月 [査読無し][通常論文]
  
• The Impact of FMISO-PET Before Treatment in Nasopharyngeal Cancer Patients

  K. Yasuda, K. Tsuchiya, S. Okamoto, R. Onimaru, T. Shiga, K. Harada, R. Suzuki, Y. Kuge, N. Tamaki, H. Shirato INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS 87 (2) S644 -S644 2013年10月 [査読無し][通常論文]
  
• 原発性肺癌に対する動体追跡照射を用いた体幹部定位放射線治療

  井上哲也, 加藤徳雄, 鬼丸力也, 榊原純, 品川尚文, 大泉聡史, 鈴木隆介, 白土博樹 日本医学放射線学会総会抄録集 72nd S271 -S271 2013年02月28日 [査読無し][通常論文]
  
• SU‐E‐T‐184: Practical Method of Scanner Stability Compensation for Film Dosimetry

  M. Ishikawa, H. Kojima, H. Tachibana, S. Tanabe, R. Suzuki, T. Minemura, N. Tohyama, Y. Narita, T. Nishio, S. Ishikura Medical Physics 40 246 2013年01月01日 [査読無し][通常論文]
   

  Purpose: In high‐accuracy radiation therapy such as intensity‐modulated radiotherapy (IMRT), dosimetric quality assurance is required to ensure the accuracy of the dose delivery. Although film dosimetry, associated with absolute dose measurement, is often used for this purpose, the uncertainty of film dosimetry is strongly influenced by the stability of the scanning device. This paper proposes a practical correction method for compensating scanner instability when making dose response curves. Methods: Gafchromic EBT3 films were irradiated with 6 MV X‐rays to 0, 10, 50, 100, 200 and 300 cGy. All films were scanned 1,000 times for 45 hours with about 2.7 minutes interval by a flat‐bed type image scanner (ES‐10000G, Seiko Epson Corp.). Pixel values for 1,000 images were automatically measured using a macro function of Image J (National Institutes of Health) to analyze the same area for each ROI, stored as the average of 50 x 50 pixel values. The stability of film measurement was assessed by analyzing optical density (OD) and corrected optical density, calculated by summing the OD of unirradiated film and net optical density (ODnet). Results: OD changes were significantly corrected, including post‐exposure density growth, compared to the original OD changes. This means that highly accurate film dosimetry, independent of the condition of the scanner device, may be possible by correcting OD with ODnet. Conclusion: In making dose response curves, dose uncertainty due to scanner device instability can be minimized by correcting OD values using the ODnet value. By using the presented method, a reduction of uncertainty in film dosimetry can be achieved. Furthermore, the procedure is simple and practical for clinical implementation. This research was supported by a grant for Clinical Cancer Research (10103757) from Ministry of Health, Labour and Welfare, Japan. © 2013, American Association of Physicists in Medicine. All rights reserved.
• SU‐E‐J‐57: A Feasibility Study On Molecular‐Imaging‐Based Real‐Time Tumor Tracking for Gated Radiotherapy

  M. Ishikawa, S. Tanabe, S. Yamaguchi, N. Ukon, T. Yamanaka, K. Sutherland, N. Miyamoto, R. Suzuki, N. Katoh, K. Yasuda, H. Shirato Medical Physics 40 162 2013年01月01日 [査読無し][通常論文]
   

  Purpose: Molecular imaging is one of the important modalities in delineating tumors particularly in radiotherapy treatment planning. If the real‐time tumor position can be detected using molecular imaging during radiotherapy, it may be helpful for gated irradiation. A feasibility study on a beam gating system for radiotherapy using real‐time molecular imaging was conducted by the prototype and simulating a parallel plane PET system. Methods: Assuming that the motion of the positron source is constrained to the central plane, the source position can be calculated from a cross point of the Line of Response (LOR) and the central plane between detector surfaces. If a positron source is located at the ISO center, distribution of the cross points might be blurred due to random/scattered coincidence. Center Located Ratio (CLR) was defined as a ratio of LORs passing through the ISO center divided by the entire LORs. When dislocation for perpendicular direction is occurred, a distribution of cross points will be spread out and associated decrease of CLR value will be expected. Results: The behavior between real measurement and simulation was similar on proto‐type experiments, however, the Result from simulation for demonstrator might be different from actual measurement. RTRT system recognizes the position of a gold marker in the rate of 30 fps using two X‐ray television systems. It is shown that 15,000 events per second will be needed for an appropriate gating irradiation to recognize discrepancy over 2mm of time resolution in the parallel plane PET system demonstrator. Conclusion: A feasibility study was carried out to verify the potential for gating irradiation of tumors with real‐time molecular imaging using a parallel plane PET system. For an parallel plane PET system demonstrator, the possibility of detecting the tumor position with an accuracy of 2 mm from the ISO center with 500 events. This research was a part of the “Innovation COE Program for Future Drug Discovery and Medical Care” project and partially supported by the Grant‐in‐Aid for Project for Developing Innovation Systems of the Japanese Ministry of Education, Culture, Sports, Science and Technology. © 2013, American Association of Physicists in Medicine. All rights reserved.
• Stereotactic Body Radiation Therapy Using Gated Radiation Therapy With Real-time Tumor-tracking for Stage I Non-small Cell Lung Cancer

  T. Inoue, N. Katoh, R. Onimaru, R. Suzuki, J. Sakakibara-Konishi, N. Shinagawa, S. Oizumi, H. Shirato INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS 84 (3) S559 -S559 2012年11月 [査読無し][通常論文]
  
• Improvement of tracking accuracy and stability by recursive image processing in real-time tumor-tracking radiotherapy system

  Naoki Miyamoto, Kenneth Sutherland, Ryusuke Suzuki, Taeko Matsuura, Chie Toramatsu, Seishin Takao, Hideaki Nihongi, Rumiko Kinoshita, Shinichi Shimizu, Rikiya Onimaru, Kikuo Umegaki, Hiroki Shirato, Masayori Ishikawa Progress in Biomedical Optics and Imaging - Proceedings of SPIE 8316 83160 2012年05月01日 [査読無し][通常論文]
   

  In the real-time tumor-tracking radiotherapy (RTRT) system, the fiducial markers are inserted in or near the target tumor in order monitor the respiratory-induced motion of tumors. During radiation treatment, the markers are detected by continuous fluoroscopy operated at 30 frames/sec. The marker position is determined by means of a template pattern matching technique which is based on the normalized cross correlation. With high tube voltage, large current and long exposure, the fiducial marker will be recognized accurately, however, the radiation dose due to X-ray fluoroscopy increases. On the other hand, by decreasing the fluoroscopy parameter settings, the fiducial marker could be lost because the effect of statistical noise is increased. In the respiratory-gated radiotherapy, the error of the image guidance will induce the reduction of the irradiation efficiency and accuracy. In order to track the marker stably and accurately in low dose fluoroscopy, we propose the application of a recursive filter. The effectiveness of the image processing is investigated by tracking the static marker and the dynamic marker. The results suggest that the stability and the accuracy of the marker tracking can be improved by applying the recursive image filter in low dose imaging. © 2012 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).
• マルチベンダに対応した放射線治療計画管理システムの開発

  辻真太朗, 鈴木隆介, 安田耕一, 藤田勝久, 宮崎智夫, 石川正純, 白土博樹 日本放射線技術学会総会学術大会予稿集 68th 134 -134 2012年02月29日 [査読無し][通常論文]
  
• リアルタイム分子イメージングを用いた治療ビームゲーティングに関する基礎検討

  右近直之, 棚邊哲史, 棚邊哲史, 山中琢, 山口哲, SUTHERLAND Kenneth, 鈴木隆介, 宮本直樹, 白土博樹, 石川正純 医学物理 Supplement 32 (3) 2012年
• SU‐E‐J‐42: Motion Adaptive Image Filter for Low Dose X‐Ray Fluoroscopy in the Real‐Time Tumor‐Tracking Radiotherapy System

  N. Miyamoto, M. Ishikawa, K. Sutherland, R. Suzuki, T. Matsuura, S. Takao, C. Toramatsu, H. Nihongi, S. Shimizu, R. Onimaru, K. Umegaki, H. Shirato Medical Physics 39 3661 -3662 2012年01月01日 [査読無し][通常論文]
   

  Purpose: In the real‐time tumor‐tracking radiotherapy system, fiducial markers are detected by X‐ray fluoroscopy. The fluoroscopic parameters should be optimized as low as possible in order to reduce unnecessary imaging dose. However, the fiducial markers could not be recognized due to effect of statistical noise in low dose imaging. Image processing is envisioned to be a solution to improve image quality and to maintain tracking accuracy. In this study, a recursive image filter adapted to target motion is proposed. Methods: A fluoroscopy system was used for the experiment. A spherical gold marker was used as a fiducial marker. About 450 fluoroscopic images of the marker were recorded. In order to mimic respiratory motion of the marker, the images were shifted sequentially. The tube voltage, current and exposure duration were fixed at 65 kV, 50 mA and 2.5 msec as low dose imaging condition, respectively. The tube current was 100 mA as high dose imaging. A pattern recognition score (PRS) ranging from 0 to 100 and image registration error were investigated by performing template pattern matching to each sequential image. The results with and without image processing were compared. Results: In low dose imaging, theimage registration error and the PRS without the image processing were 2.15±1.21 pixel and 46.67±6.40, respectively. Those with the image processing were 1.48±0.82 pixel and 67.80±4.51, respectively. There was nosignificant difference in the image registration error and the PRS between the results of low dose imaging with the image processing and that of high dose imaging without the image processing. Conclusions: The results showed that the recursive filter was effective in order to maintain marker tracking stability and accuracy in low dose fluoroscopy. © 2012, American Association of Physicists in Medicine. All rights reserved.
• 5-224 北海道大学大学院工学院における医学物理士・放射線治療品質管理士コース((02)専門科目の講義・演習-III,口頭発表論文)

  古坂 道弘, 鬼柳 善明, 住吉 孝, 白土 博樹, 石川 正純, 鈴木 隆介 工学教育研究講演会講演論文集 23 (59) 356 -357 2011年08月22日 [査読無し][通常論文]
  
• 頭頸部リンパ節腫瘍における放射線治療効果予測

  高尾聖心, 但野茂, 田口大志, 安田耕一, 鬼丸力也, 石川正純, 鈴木隆介, GERARD Bengua, 白土博樹 日本生体医工学会大会プログラム・論文集(CD-ROM) 50th ROMBUNNO.O1-9-5 2011年 [査読無し][通常論文]
  
• 鼻腔・副鼻腔癌に対する超選択的動注を併用した根治的化学放射線療法

  長谷川雅一, 安田耕一, 吉田大介, 加藤徳雄, 鬼丸力也, 浅野剛, 白土博樹, 本間明宏, 折舘伸彦, 福田諭, 石川正純, BENGUA Gerard, SUTHERLAND Kenneth, 宮本直樹, 鈴木隆介 Jpn J Radiol 28 (Supplement 1) 7 -7 2010年07月25日 [査読無し][通常論文]
  
• 診断X線領域における極微小SOF線量計による被曝線量評価

  石川正純, 江口菜弥帆, 作原大介, 阿保大介, 太田真緒, SUTHERLAND Kenneth, BENGUA Gerard, 鈴木隆介, 宮本直樹, 白土博樹 日本医学放射線学会総会抄録集 69th S378 -S378 2010年02月28日 [査読無し][通常論文]
  
• Improvement of Tracking Accuracy and Stability with Utilizing a Color Image Intensifier in Real-time Tumor-tracking Radiotherapy System

  N. Miyamoto, M. Ishikawa, G. Bengua, K. Sutherland, R. Suzuki, H. Shirato INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS 78 (3) S678 -S678 2010年 [査読無し][通常論文]
  
• Conceptual Design of PET-linac System for Molecular-guided Radiotherapy

  M. Ishikawa, S. Yamaguchi, S. Tanabe, G. Bengua, K. Sutherland, R. Suzuki, N. Miyamoto, K. Nishijima, N. Katoh, H. Shirato INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS 78 (3) S674 -S674 2010年 [査読無し][通常論文]
  
• Feasibility Study on Molecular-imaging Based Tracking System for Lung Cancer Treatment

  S. Tanabe, M. Ishikawa, S. Yamaguchi, G. Bengua, K. Sutherland, R. Suzuki, N. Miyamoto, N. Katoh, R. Onimaru, H. Shirato INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS 78 (3) S749 -S749 2010年 [査読無し][通常論文]
  
• ^<12>Cにおける3α共鳴状態とクラスター構造(クラスター模型による、共鳴、反応の理論、天体核反応への応用,原子核クラスター物理の現状と展望,研究会報告)

  黒河 千恵, 鈴木 隆介, 加藤 幾芳 素粒子論研究 115 (4) D32 -D33 2007年10月20日 [査読無し][通常論文]
  
• 24pYE-1 複素座標スケーリング法による散乱問題の3α模型への適用(24pYE 核反応,理論核物理領域)

  鈴木 隆介, 黒河 千恵, Kruppa A.T, 加藤 幾芳 日本物理学会講演概要集 62 (2) 58 -58 2007年08月21日 [査読無し][通常論文]
  
• 28pSB-1 複素座標スケーリング法による散乱問題(28pSB 核反応・核分裂,理論核物理領域)

  鈴木 隆介, 阿部 大志, 黒河 千恵, Kruppa A. T, Giraud B. G, 加藤 幾芳 日本物理学会講演概要集 62 (1) 52 -52 2007年02月28日 [査読無し][通常論文]
  
• 25aSB-11 ^<12>Cにおける0^+共鳴状態の構造と散乱への寄与II(25aSB 核構造(少数系・殻模型・クラスター),理論核物理領域)

  黒河 千恵, 鈴木 隆介, 阿部 大志, 加藤 幾芳 日本物理学会講演概要集 62 (1) 28 -28 2007年02月28日 [査読無し][通常論文]
  
• 23aSC-6 複素座標スケーリング法による^8Be+αの散乱(23aSC 原子核反応・分裂・融合,理論核物理領域)

  阿部 大志, 黒河 千恵, 鈴木 隆介, 加藤 幾芳 日本物理学会講演概要集 61 (2) 23 -23 2006年08月18日 [査読無し][通常論文]
  
• 30aWG-8 ^<12>Cにおける第3番目の0^+状態の構造(30aWG 核構造(量子多体基礎論・クラスター・殻模型),理論核物理領域)

  黒河 千恵, 鈴木 隆介, 加藤 幾芳 日本物理学会講演概要集 61 (1) 48 -48 2006年03月04日 [査読無し][通常論文]
  
• 29pWF-6 複素座標スケーリング法による散乱状態の研究(29pWF 超重核・核反応,理論核物理領域)

  鈴木 隆介, Kruppa A.T, 加藤 幾芳 日本物理学会講演概要集 61 (1) 42 -42 2006年03月04日 [査読無し][通常論文]
  
• Level density in the complex scaling method

  Ryusuke Suzuki, Takayuki Myo, Kiyoshi Kato Progress of Theoretical Physics 113 (6) 1273 -1286 2005年06月 [査読無し][通常論文]
   

  It is shown that the continuum level density (CLD) at unbound energies can be calculated with the complex scaling method (CSM), in which the energy spectra of bound states, resonances and continuum states are obtained in terms of L2 basis functions. In this method, the extended completeness relation is applied to the calculation of the Green functions, and the continuum-state part is approximately expressed in terms of discretized complex scaled continuum solutions. The obtained result is compared with the CLD calculated exactly from the scattering phase shift. The discretization in the CSM is shown to give a very good description of continuum states. We discuss how the scattering phase shifts can inversely be calculated from the discretized CLD using a basis function technique in the CSM.
• 24pWG-2 ^<12>Cにおける3α共鳴状態の波動関数の分析(核構造・多体基礎論,理論核物理)

  黒河 千恵, 鈴木 隆介, 加藤 幾芳 日本物理学会講演概要集 60 (1) 36 -36 2005年03月04日 [査読無し][通常論文]
  
• 24pWG-3 複素座標スケーリング法による共鳴状態の波動関数の分析(核構造・多体基礎論,理論核物理)

  鈴木 隆介, 明 孝之, 加藤 幾芳 日本物理学会講演概要集 60 (1) 36 -36 2005年03月04日 [査読無し][通常論文]
  
• Level density in complex scaling method

  R Suzuki, T Myo, K Kato Few-Body Problems in Physics 768 455 -455 2005年 [査読無し][通常論文]
  
• Continuum level density in complex scaling method

  R Suzuki, T Myo, K Kato Exotic Nuclear Systems 802 129 -132 2005年 [査読無し][通常論文]
   

  A new calculational method of continuum level density (CLD) at unbound energies is studied in the complex scaling method (CSM). It is shown that the CLD can be calculated by employing the discretization of continuum states in the CSM without any smoothing technique.
• 28pSG-2 複素座標スケーリング法による状態密度(核構造・多体基礎論/核反応/超重核, 理論核物理)

  鈴木 隆介, 明 孝之, 加藤 幾芳 日本物理学会講演概要集 59 (2) 32 -32 2004年08月25日 [査読無し][通常論文]
  
• 28pSB-7 ^<10>Be+n+^<12>C 模型による ^<11>Be 核の分解反応の研究

  鈴木 隆介, 明 孝之, 加藤 幾芳, 池田 清美 日本物理学会講演概要集 58 (1) 41 -41 2003年03月06日 [査読無し][通常論文]
  
• Analysis of ¹¹Be in the ¹⁰Be + n model

  Ryusuke Suzuki, Takayuki Myo, Kiyoshi Kato, Kiyomi Ikeda Progress of Theoretical Physics 626 -627 2002年12月01日 [査読無し][通常論文]
  
• 13pRF-7 ^10Be+n模型を用いた^11Be核の分解反応の解析(核反応・不安定核・超重核,理論核物理)

  鈴木 隆介, 明 孝之, 加藤 幾芳, 池田 清美 日本物理学会講演概要集 57 (2) 23 -23 2002年08月13日
• 27pXA-2 ^<10>Be+n模型を用いた^<11>Be核のクーロン分解反応の解析

  鈴木 隆介, 明 孝之, 加藤 幾芳, 池田 清美 日本物理学会講演概要集 57 (1) 28 -28 2002年03月01日 [査読無し][通常論文]
  
• 23aSH-4 変形と対相関の効果を考慮した^<11>Be核の構造解析

  鈴木 隆介, 明 孝之, 加藤 幾芳, 山田 泰一, 池田 清美 日本物理学会講演概要集 54 (2) 24 -24 1999年09月13日 [査読無し][通常論文]
  
• ^<11>Beの低励起状態(軽い不安定核の構造とクラスター構造,不安定核の構造と反応,研究会報告)

  鈴木 隆介, 加藤 幾芳, 明 孝之, 山田 泰一, 池田 清美 素粒子論研究 99 (5) E119 -E122 1999年08月20日 [査読無し][通常論文]
  
• 31a-YG-4 <11>^Be核のパリティ逆転問題と励起状態の解析

  鈴木 隆介, 加藤 幾芳, 明 孝之, 山田 泰一, 池田 清美 日本物理学会講演概要集 54 (1) 39 -39 1999年03月15日 [査読無し][通常論文]
  
• 6a-C-6 ^<11>Be核s-軌道問題における変形効果と対相関の競合

  加藤 幾芳, 鈴木 隆介, 明 孝之, 山田 泰一, 池田 清美 日本物理学会講演概要集 53 (2) 43 -43 1998年09月05日 [査読無し][通常論文]
  

共同研究・競争的資金等の研究課題

• 肺癌に対する陽子線治療の選択基準確立に向けた心肺相互作用勘案NTCPモデル構築

  日本学術振興会：科学研究費助成事業 基盤研究(B)

  研究期間 : 2022年04月 -2025年03月 

  代表者 : 青山 英史, 鈴木 隆介, 宮本 直樹, 高尾 聖心, 金平 孝博, 橋本 孝之, 小橋 啓司, 西岡 健太郎, 田口 大志
• 次世代の体幹部定位放射線治療を実現する動体追跡回転照射の基盤技術開発

  日本学術振興会：科学研究費助成事業 基盤研究(B)

  研究期間 : 2017年04月 -2020年03月 

  代表者 : 宮本 直樹, 鬼丸 力也, 富岡 智, 鈴木 隆介, 前田 憲一郎

   

  本研究では、次世代の体幹部定位放射線治療技術として、動体追跡回転照射の基盤技術の研究開発を実施した。動体追跡回転照射に見込まれる治療時間を体内マーカの軌跡ログデータから評価し、安定した呼吸性運動の場合においては現行の固定多門型の動体追跡治療と比較して治療時間を低減できることがわかった。また、実際の治療装置を用いた動体追跡回転照射による線量分布をフィルムにより評価し、臨床的に許容できる線量分布が得られることを確認した。電離箱線量計による評価では、計画値と実測値の線量誤差は3%以内であり、一連の評価から、提案する動体追跡回転照射の有用性を示した。
• 線量勾配を考慮した新しい線量分布解析法の確立

  日本学術振興会：科学研究費助成事業 基盤研究(B)

  研究期間 : 2015年04月 -2018年03月 

  代表者 : 石川 正純, 鈴木 隆介, 橋本 成世

   

  本研究の目的は、放射線治療におけるフィルムを用いた線量分布評価法として、線量勾配を考慮した新しい解析方法であるGradient法を確立することである。一般的に、放射線計測はポアソン統計に従うことから、統計学に基づいた判定基準を提案した。統計学的な評価を可能とするために、測定に起因する不確かさおよび位置ずれに起因する不確かさを評価する手法を開発し、複数の施設にて実測による検証を行った。
• 動体追跡装置を用いた『体内臓器の動き』のモデル化に関する研究

  日本学術振興会：科学研究費助成事業 若手研究(B)

  研究期間 : 2012年04月 -2015年03月 

  代表者 : 鈴木 隆介

   

  北海道大学病院において動体追跡装置を用いて測定された臓器の動きに関するデータベースの構築を継続して進め、このデータベースを元にした動きの解析を行った。動体追跡装置で得られるログの中に存在する、せきなどにより大きく動いた場合や、透視条件が悪い時などに動体追跡装置が追跡のマーカを認識できなくなる際に起こる動きのアーチファクトの影響を考慮するインタフェースの実装を行った。この構築したデータベースを基盤とした、臓器の動きに関してのモデル化のアルゴリズムの開発を行った。
• 動体追跡装置を用いた『体内臓器の動き』のデータベース化に関する研究

  日本学術振興会：科学研究費助成事業 若手研究(B)

  研究期間 : 2009年 -2010年 

  代表者 : 鈴木 隆介

   

  北海道大学病院において動体追跡装置を用いて測定された臓器の動きに関するデータを収集して一元化し、系統的な臓器の動きを把握する基盤(データベース)を、利用者側が容易に利用できるようにウェブ形式のシステムとして構築した。本研究において作成されたデータベースを用い、体内での臓器の動きのメカニズムの把握、研究を行う枠組みの検討を行い、構築したデータベースを用いて臓器の動きの解析を行った。
• 相互作用放射線治療

  日本学術振興会：科学研究費助成事業 基盤研究(A)

  研究期間 : 2006年 -2008年 

  代表者 : 白土 博樹, 本間 さと, 玉木 長良, 久下 裕司, 伊達 広行, 鬼柳 善明, 畠山 昌則, 金子 純一, 水田 正弘, 犬伏 正幸, 但野 茂, 田村 守, 早川 和重, 松永 尚文, 石川 正純, 青山 英史, 作原 祐介, 鬼丸 力也, 阿保 大介, 笈田 将皇, 神島 保, 寺江 聡, 工藤 與亮, 小野寺 祐也, 尾松 徳彦, 清水 伸一, 西村 孝司, 鈴木 隆介, ジェラード ベングア

   

  いままでの先端放射線医療に欠けていた医療機器と患者のinteractionを取り入れた放射線治療を可能にする。臓器の動き・腫瘍の照射による縮小・免疫反応などは、線量と時間に関して非線形であり、システムとしての癌・臓器の反応という概念を加えることが必要であることが示唆された。生体の相互作用を追求していく過程で、動体追跡技術は先端医療のみならず、基礎生命科学でも重要な役割を果たすことがわかった。

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委員歴

• 2022年04月 - 現在   日本医学物理学会   代議員
• 2019年04月 - 現在   医学物理士認定機構   専門試験委員会 委員
• 2013年04月 - 現在   医学物理士認定機構   教育コース認定委員会 委員
• 2015年04月 - 2019年03月   医学物理士認定機構   企画調整委員会 委員